Frequently Asked Questions

Introduction

A1. What is CVE?

CVE is a list of information security vulnerabilities and exposures that aims to provide common names for publicly known problems. The goal of CVE is to make it easier to share data across separate vulnerability capabilities (tools, repositories, and services) with this "common enumeration."

A2. What is a "vulnerability"?

An information security vulnerability is a mistake in software that can be directly used by a hacker to gain access to a system or network. See the Terminology page for a complete explanation of how this term is used on the CVE Web site.

A3. What is an "exposure"?

An information security exposure is a mistake in software that allows access to information or capabilities that can be used by a hacker as a stepping-stone into a system or network. See the Terminology page for a complete explanation of how this term is used on the CVE Web site.

A4. Why CVE? Is there a lot of support for something like this?

Using a common identifier makes it easier to share data across separate databases, tools, and services, which until the creation of CVE in 1999, were not easily integrated. If a report from a security capability incorporates CVE identifiers, you may then quickly and accurately access fix information in one or more separate CVE-compatible tools, services, and repositories to remediate the problem. With CVE, your tools and services can "speak" (i.e., exchange data) with each other. You'll know exactly what each covers because CVE provides you with a baseline for evaluating the coverage of your tools. This means you can determine which tools are most effective and appropriate for your organization's needs. In short, CVE-compatible tools, services, and databases will give you better coverage, easier interoperability, and enhanced security.

CVE is industry endorsed by the CVE Editorial Board and the numerous organizations that have declared their products CVE-compatible or include CVE identifiers in their vendor alerts and security advisories. CVE content is approved by the CVE Editorial Board, which is comprised of leading representatives from the information security community.

A5. Is CVE intended for public use? Where can I get the latest copy of CVE?

CVE is free to use and publicly available to anyone interested in correlating data between different vulnerability or security tools, repositories, and services. You may search or download CVE, copy it, redistribute it, reference it, and analyze it, provided you do not modify CVE itself. You may also link to specific CVE identifier pages from your Web site, product, publication, or other capability.

A6. Who owns CVE?

The MITRE Corporation maintains CVE and this public Web site, manages the compatibility program, and provides impartial technical guidance to the CVE Editorial Board throughout the process to ensure CVE serves the public interest.

A7. Isn't CVE just another vulnerability database?

No. CVE is not a vulnerability database. CVE is designed to allow vulnerability databases and other capabilities to be linked together, and to facilitate the comparison of security tools and services. As such, CVE does not contain information such as risk, impact, fix information, or detailed technical information. CVE only contains the standard identifier number with status indicator, a brief description, and references to related vulnerability reports and advisories. (Note: The U.S. National Vulnerability Database (NVD) provides fix and other information for identifiers on the CVE List.)

A8. How does a vulnerability or exposure become a CVE Identifier?

The process begins with the discovery of a potential security vulnerability or exposure. The information is then assigned a CVE Identifiers with candidate status (also called a candidate, candidate number, or CAN) by a CVE Candidate Numbering Authority (CNA), posted on the CVE Web site, and is proposed to the Board by the CVE Editor. As part of its management of CVE, The MITRE Corporation functions as Editor and Primary CNA The CVE Editorial Board discusses the candidate and votes on whether or not it should become an official CVE entry. If the candidate is rejected, the reason for rejection is noted in the Editorial Board Archives posted on the CVE Web site. If the candidate is accepted, its status is updated to "entry" on the CVE List. However, the assignment of a candidate number is not a guarantee that it will become an official CVE entry. For more a more detailed description of this process, refer to About CVE Identifiers, CVE Editorial Policies, and How We Build the CVE List.

A9. Where does CVE find out about these vulnerabilities and exposures?

CVE is based on publicly available information. Primarily, MITRE receives its vulnerability information from the organizations that serve as its data sources, Internet Security Systems (ISS), SecurityFocus, Neohapsis, and the U.S. National Infrastructure Protection Center. Throughout the life of the CVE List, MITRE has relied on external data sources to identify vulnerabilities. In addition, candidates for possible new vulnerabilities and exposures are reserved regularly by the CVE Candidate Numbering Authorities and then included in their vendor and security community alerts and advisories. As a result, MITRE can concentrate on devising the standard names rather than "reinventing the wheel" and conducting the research required to find the initial vulnerability reports.

A10. Does CVE contain all vulnerabilities and exposures?

No. The intention of CVE is to be comprehensive with respect to all publicly known vulnerabilities and exposures. While CVE is designed to contain mature information, our primary focus is on identifying vulnerabilities and exposures that are detected by security tools and any new problems that become public, and then addressing any older security problems that require validation.

A11. What is the difference between CVE Identifiers and Bugtraq IDs?

Bugtraq IDs are identifiers for a commercially operated vulnerability database that are used in security advisories and alerts, as well as for discussions on the Bugtraq mailing list. CVE identifiers are from an international information security effort that is publicly available and free to use. CVE identifiers are for the sole purpose of providing a common name. For this reason, CVE Identifiers are frequently used by researchers and the makers of security tools, Web sites, databases, and services as a standard method for identifying vulnerabilities and for cross-linking with other repositories that also use CVE identifiers. CVE identifiers with candidate status are used in the same manner as CVE Identifiers with entry status, since many of them will eventually be officially added to the CVE List as official CVE entries.

Note also that SecurityFocus, which runs Bugtraq, is a member of the CVE Editorial Board, includes CVE Identifiers in its security announcements, and is listed on the CVE-Compatible Products and Services page.

A12. What is the FBI/SANS Top Twenty list? How is CVE involved?

The SANS/FBI Twenty Most Critical Internet Security Vulnerabilities is a consensus list of the most critical problem areas in Internet security that require immediate remediation if present on your systems. Step-by-step instructions and pointers to additional information useful for correcting these security flaws are included as part of the list.

The SANS/FBI list includes CVE Identifiers to uniquely identify the vulnerabilities it describes. This helps system administrators use CVE-Compatible Products and Services to make their networks more secure.

A13. I discovered a new vulnerability or exposure. How can I obtain a CVE number?

In most instances CVE relies on certain mechanisms to handle newly emerging information. To obtain a candidate number you could post information to mailing lists such as Bugtraq or NTBugtraq; contact an emergency response team such as CERT/CC, DOE-CIAC, CanCERT, etc.; contact a vulnerability analysis team; or contact a CVE " Candidate Numbering Authority (CNA)." CNAs are organizations that distribute CVE candidate numbers to researchers and information technology vendors for inclusion in first-time public announcements of new vulnerabilities (see the Candidate Numbering Authorities page for more information). If the organization you contact is a CNA, they will include a CVE candidate number(s) in their initial public announcement about your new vulnerability. Thus, new entries will make it into CVE once they have been verified through these other mechanisms.

Alternatively, you may contact cve@mitre.org and we will provide you with our "CVE Candidate Reservation Guidelines For Researchers" and work with you to assign a CVE candidate number while you work through the process of publicly disclosing the vulnerability. Please review the Researcher Responsibilities on the Candidate Numbering Authorities page before proceeding.

A14. How can CVE help me?

A CVE Identifier will give you a standardized identifier for any given vulnerability or exposure. Knowing this identifier will allow you to quickly and accurately access information about the problem across multiple information sources that are CVE-compatible. For example, if you own a security tool whose reports contain references to CVE Identifiers, you may then access fix information in a separate CVE-compatible database. CVE also provides you with a baseline for evaluating the coverage of your tools. With CVE's common names, you'll know exactly what each tool covers allowing you to determine which tools are most effective and appropriate for your organization's needs.

In addition, if the security advisories your organization receives are CVE-compatible, you can see if your vulnerability scanners check for this threat and then determine whether your intrusion detection system has the appropriate attack signatures to identify attempts to exploit particular vulnerabilities. If you build or maintain systems for customers, the CVE compatibility of advisories will help you to directly identify any fixes from the vendors of the commercial software products in those systems (if the vendor fix site is CVE-compatible). See Enterprise Security Enabled by CVE for additional information.

A15. How can my organization and I be involved?

Network Security Administrators/Policy and Decision Makers: Adopt CVE-compatible products/services or encourage your vendors to be CVE-compatible to support your enterprise requirements.

Security Vendors/Vulnerability Database Managers/Service Providers: Deliver CVE-compatible tools, databases, or services to your customers for better coverage, easier interoperability, and enhanced security across the enterprise.

Software Venders: Incorporate the use and reservation of CVE Identifiers into your vulnerability handling process so that your customers can work with concise information and leverage the power of vulnerability scanners to verify that updates and fixes have been applied.

A16. Is someone from CVE available to speak or participate on panel discussions at industry-related events, meetings, etc.?

Yes, members of the CVE and the Common Configuration Enumeration (CCE™), Common Weakness Enumeration (CWE), Open Vulnerability and Assessment Language (OVAL), and Common Malware Enumeration (CME™) projects are available to present or participate in panel discussions about CVE and/or other vulnerability management topics. Contact cve@mitre.org for more information and availability.

A17. Does CVE participate in link exchange arrangements?

No, CVE does not exchange links with other Web sites. Only authorized links are allowed on the CVE Web site such as references for CVE Identifiers and those for CVE-Compatible Products and Services, CVE Editorial Board Members, CVE Sponsors, and News about CVE.

B. CVE List

B1. What is a CVE Identifier?

CVE Identifiers (also called "CVE names," "CVE numbers," "CVE-IDs," and "CVEs") are unique, common identifiers for publicly known information security vulnerabilities.

Each CVE Identifier includes the following:

• CVE identifier number (i.e., "CVE-1999-0067").
• Indication of "entry" or "candidate" status.
• Brief description of the security vulnerability or exposure.
• Any pertinent references (i.e., vulnerability reports and advisories or OVAL-ID).

CVE Identifiers are used by information security product/service vendors and researchers as a standard method for identifying vulnerabilities and for cross-linking with other repositories that also use CVE Identifiers.

B2. What is "entry" status?

CVE Identifiers have "entry" or "candidate" status. Entry status indicates that the CVE Identifier has been accepted to the CVE List while candidate status indicates that the Identifiers is under review for inclusion in the list. See the About CVE Identifiers section for additional information.

B3. What is "candidate" status?

CVE Identifiers with candidate status (also called "candidates," "candidate numbers," or "CANs") are those vulnerabilities or exposures under consideration for acceptance into CVE. They reflect breaking and newly discovered vulnerability information that may be of special or immediate concern to the public, while official entries are considered mature and reviewed information. The assignment of a candidate is not a guarantee that the name will become an official CVE entry. See the About CVE Identifiers section for additional information.

B4. Are there references available for CVE Identifiers?

Each CVE Identifier includes appropriate references. The CVE Web site also includes a Reference Maps page with links to documents from the commonly used information sources that are used as references for CVE entries and candidates. Each reference used in CVE (1) identifies the source, (2) includes a well-defined identifier to facilitate searching on a source's Web site, and (3) notes the associated CVE Identifier.

B5. How often are new CVE versions released?

New CVE versions are created periodically, once per annum at most. When they are released Version Reports are also made available that list the differences between versions. We announce new CVE versions on the News and Events page of the CVE Web site and on our free e-newsletter, "CVE-Announce".

B6. Does CVE have an RSS Feed (XML)?

CVE itself does not currently offer an RSS feed, however, the U.S. National Vulnerability Database (NVD) provides (an RSS feed of all recently assigned CVE Identifiers with candidate status, and (2) an RSS feed of all fully analyzed CVE Identifiers, which includes the names of the vulnerable products in the headers.

In addition, CVE Change Logs a free tool from CERIAS/Purdue University allows users to obtain daily or monthly changes to CVE identifiers with entry status and CVE Identifiers with candidate status.

B7. Does CVE have a procedure for determining how to assign candidate numbers to newly discovered vulnerabilities?

Yes. CVE editorial policies, or "content decisions" (CDs), are the criteria and consistency rules that determine (1) what security issues become CVE candidates for eventual inclusion in the CVE List, and (2) how we distinguish between similar or security related issues.

Generally, the CVE approach is to create separate candidates for:

• Vulnerabilities of different types
• Vulnerabilities of the same type that appear in different versions
• Vulnerabilities that appear in different codebases (i.e., "by vendor;" however, this also includes vendors who share the same code such as Linux/Unix vendors)

See CVE Editorial Policies for a detailed description and examples of this process.

B8. How long does it take for a candidate to become a CVE entry?

In general it takes one day to one month to assign a candidate number, and a year or more for the typical candidate to become an official CVE entry. However, some candidates can be delayed for much longer because the issues are obscure or insufficiently verified, or they are being held back because the surrounding CVE Editorial Policies have not been stabilized.

See the About CVE Identifiers section for additional information.

B9. Does every CVE entry start as a candidate?

Yes, every CVE entry starts as a candidate. See A8. "How does a vulnerability or exposure become a CVE Identifier?"

B10. How can I find out when new candidates are added to the CVE Web site?

A free tool from CERIAS/Purdue University monitors changes to the CVE List. "CVE Change Logs" allows you to obtain daily or monthly changes to both lists. The tool is a feature of CERIAS' Cassandra incident response database service, which is listed on the CVE-Compatible Products and Services page.

In addition, a list of recently assigned CVE candidates is included on the homepage of the U.S. National Vulnerability Database (NVD).

C. Using CVE

C1. How do I search CVE?

There are three ways to obtain CVE data: View CVE, Download CVE, or Search CVE.

• The View option will provide an HTML formatted listing of the current version of the CVE List. The top of the HTML listing will have a heading in the following format: CVE (version 19990929). This indicates it is a listing of all entries in CVE as of the version date, which is in the format "YearMonthDay."
• The Download option will allow you to download the entire CVE List in various formats: (HTML, Text, or comma separated).
• The Search option allows you to search CVE by keywords or by CVE Identifier. NOTE: if you search by keyword, the search engine will also return relevant candidates.

Refer to the CVE List section for more information.

C2. I don't understand these entries. What's a "buffer overflow" anyway?

CVE is intended for use by security experts, so it assumes a certain level of knowledge. It is intentionally designed to be as compact and concise as possible. Other sources of information (such as CVE-compatible Web sites and training resources) would be more appropriate for learning about vulnerabilities and exposures.

C3. I searched CVE and I got two results back. How can I tell which is the one I want?

While the description for a CVE Identifiers should be able to uniquely identify a vulnerability or exposure, they are intentionally brief, and in some instances you may need to rely on the accompanying references to make a determination. When this occurs it is either because not enough details about the problem were originally provided, because the description includes unique details that you may not be familiar with, or because of an error in the description itself. In addition to referring to the references, you could also search through CVE-compatible sites by specifying the CVE Identifiers that you are uncertain about.

(Note: The U.S. National Vulnerability Database (NVD) provides fix and other information for identifiers on the CVE List.)

C4. Can I search CVE by operating system?

The CVE search was designed to help identify specific vulnerabilities and exposures, and not to find sets of problems that share common attributes such as operating systems. Therefore, you should not search CVE by operating system because your results will be incomplete.

Note: The U.S. National Vulnerability Database (NVD), which is based upon and synchronized with the identifiers on the CVE List, is searchable by operating system.

C5. Why doesn't CVE include fix information, impact, classification, or other important technical details?

This information can already be found in numerous vulnerability Web sites, databases, and security tool databases. CVE doesn't have this information because CVE is intended to link these different vulnerability capabilities, not to replace them.

Note: The U.S. National Vulnerability Database (NVD) provides fix and other information for identifiers on the CVE List.

C6. Why doesn't CVE use a taxonomy?

Developing a universally applicable taxonomy for vulnerabilities is an ongoing area of research. One goal of CVE is to capture community agreement. The enumeration and categorization of vulnerabilities are different (albeit related) efforts. The effort of building and populating the CVE List may facilitate further advances in the study of vulnerability taxonomies.

C7. Can't hackers use this to break into my network?

Any public discussion of vulnerability information may help a hacker. However, there are several reasons why the benefits of CVE outweigh its risks:

• CVE is restricted to publicly known vulnerabilities and exposures.
• For a variety of reasons, sharing information is more difficult within the information security community than it is for hackers.
• It takes much more work for an organization to protect its networks and fix all possible holes than it takes for a hacker to find a single vulnerability, exploit it, and compromise the network.
• There is a shift in community opinion towards sharing information, as reflected in the fact that the CVE Editorial Board includes key organizations in information security.

C8. Someone has hacked into my Web site. Can CVE help me recover?

CVE cannot help you to determine precisely what vulnerability an attacker may have exploited to obtain unauthorized access. But once you determine what vulnerability was exploited, you could find the CVE Identifier and use it to examine CVE-compatible information sources in order to obtain fix information, technical details, and other information that will be helpful to you.

C9. How can CVE help me protect my network?

By using the CVE Identifier for a particular vulnerability or exposure, you will be able to quickly and accurately obtain information from a variety of CVE-compatible information sources. By facilitating better comparisons between different security tools and services, CVE can help you make a better choice as to which of these capabilities are appropriate for your needs. You may also be able to create a suite of interoperable security tools and capabilities from multiple vendors, if those tools and capabilities incorporate CVE as a translation mechanism.

Using CVE-Compatible Products and Services will allow you to improve how your organization responds to security advisories. If the advisory is CVE-compatible, you can see if your scanners or security service checks for this threat and then determine whether your intrusion detection system has the appropriate attack signatures. If you build or maintain systems for customers, the CVE compatibility of advisories will help you to directly identify any fixes from the vendors of the commercial software products in those systems (if the vendor fix site is CVE-compatible).

Other indirect benefits may also arise from CVE. For example, it facilitates better research on vulnerabilities and exposures. See Enterprise Security Enabled by CVE for additional information.

C10. How will CVE help me compare security tools?

With CVE, your vulnerability databases, services, and tools can "speak" to each other. Until the creation of CVE in 1999 it was very difficult to effectively decide which tool was the most appropriate for an organization's needs. Each vendor used a different definition of "vulnerability" or "exposure" and used different metrics to state how many vulnerabilities or exposures they "check" or "test." CVE provides vendors with a standard list they can compare to, thus allowing you to compare apples to apples. In the longer term, CVE may be useful for obtaining quantitative data on tool behaviors, such as how they perform their checks, the impact they have on the systems they examine, the rate of false positives or false negatives, or how quickly they update their tools when new entries are introduced into CVE.

C11. Can I include CVE Identifiers in my product/database/security advisory/etc.?

Yes, CVE is free to use. You may search or download CVE, copy it, redistribute it, reference it, and analyze it, provided you do not modify CVE itself. You may also link to specific CVE entry and candidate pages from your Web site, product, publication, or other capability. In addition, CVE entries and candidates are already being included in a number of security advisories (see the Organizations with CVE Identifiers in Advisories page), and numerous companies and organizations are making their information security products CVE-compatible. Visit the CVE-Compatible Products and Services page for the most current information regarding the types and availability of CVE-compatible products and services.

C12. How can I get a copy of CVE?

CVE is freely available for download, or you may search or view CVE on the Web site. The Download option allows you to download the entire CVE in various formats: HTML, Text, or comma separated. Refer to the CVE List section for more information.

D. CVE Compatibility

D1. What does it mean to be "CVE-compatible"?

"CVE-compatible" means that a tool, Web site, database, or other security product or service uses CVE Identifiers in a manner that allows it to be cross-referenced with other products that employ CVE Identifiers. CVE-compatible means:

• CVE SEARCHABLE - A user can search using a CVE Identifier to find related information.
• CVE OUTPUT - Information is presented that includes the related CVE Identifier(s).
• MAPPING - The repository owner has provided a mapping relative to a specific version of CVE, and has made a good faith effort to ensure accuracy of that mapping.
• DOCUMENTATION - The organization's standard documentation includes a description of CVE, CVE compatibility, and the details of how its customers can use the CVE-related functionality of its product or service.

Different tools provide different coverage/cross-referencing of CVE Identifiers (e.g., some tools might cover Unix, while others cover Windows NT). You will need to evaluate any CVE-compatible products and services based upon your organization's specific requirements. Visit the CVE-Compatible Products and Services page for the most current information regarding the types and availability of CVE-compatible products and services.

D2. How can my product or service be made CVE-compatible?

See "Requirements and Recommendations for CVE Compatibility" for detailed information.

D3. Can my organization register our product or service as CVE-compatible?

Any organization with a security product or service that uses CVE Identifiers in a way that allows it to cross-link with other products or services that use CVE Identifiers may request to register as CVE-compatible. The organization will need fulfill the conditions listed in the "CVE Compatibility Process," which includes two phases: (1) the Declaration Phase in which the organization declares its intent to make its product(s) and/or service(s) CVE-compatible; and (2) the Evaluation Phase, which requires the completion of a questionnaire that specifically looks for the details of how the organization has satisfied the "Requirements and Recommendations for CVE Compatibility" document. An organization must complete phase 1 before being eligible for phase 2. Organizations that successfully complete the second phase will be included in a branding program that offers an official CVE-Compatible Product/Service logo to indicate compatibility, among other benefits.

To begin the registration process, review the official CVE Compatibility Process then send an email to cve@mitre.org with your company name and contact information, the type of product, and the name of the product or service.

D4. Do security advisories and vendor alerts incorporate CVE Identifiers? How can this help me?

Yes, numerous organizations incorporate CVE Identifiers with entry and candidate status in their advisories and alerts. If an advisory is CVE-compatible, you can see if your CVE-compatible scanners check for this threat and then determine whether your CVE-compatible intrusion detection system has the appropriate attack signatures. If your software vendor uses CVE Identifiers in their security advisories you can use CVE-compatible vulnerability scanners to check whether the fixes have been applied. Finally, if you build or maintain systems for customers, the CVE compatibility of advisories will help you to directly identify any fixes from the vendors of the commercial software products in those systems (if the vendor fix site is CVE-compatible).

E. CVE Community

E1. Who is the CVE Editorial Board?

The CVE Editorial Board includes representatives from numerous security-related organizations such as security tool vendors, security service providers, academic institutions, and government, as well as other prominent security experts. Refer to the CVE Editorial Board page for a complete list of member organizations.

E2. Is there a difference between the Editorial Board discussions and the threads about vulnerabilities on mailing lists like Bugtraq and NTBugtraq?

The Bugtraq mailing lists primarily involve discussion of newly emerging vulnerability information, as well as other topics related to security. Often, initial reports are incomplete, inaccurate, or unverifiable. By contrast, the CVE Editorial Board determines when a problem is truly unique and should be added to the official CVE List. In addition, the Editorial Board discusses high-level CVE content decisions and other issues related to linking vulnerability databases via CVE. These discussions, posted in the Editorial Board Archives, are often beyond the scope of the Bugtraq mailing lists. (See A11. What is the difference between CVE Identifiers and Buqtraq IDs?)

E3. What is MITRE's role in CVE?

The MITRE Corporation manages and maintains the CVE List with assistance from the CVE Editorial Board, conducts community outreach activities, maintains the CVE Web site, manages the CVE compatibility program, and provides neutral guidance throughout the process to ensure that CVE serves the public interest.

In partnership with government clients, The MITRE Corporation is a not-for-profit corporation working in the public interest. It addresses issues of critical national importance, combining systems engineering and information technology to develop innovative solutions that make a difference.

MITRE's work is focused within three Federally Funded Research and Development Centers (FFRDCs). One FFRDC performs systems engineering and integration work for Department of Defense C3I. A second performs systems research and development work for the Federal Aviation Administration and other civil aviation authorities. The third FFRDC provides strategic, technical and program management advice to the Internal Revenue Service and the Treasury Department. An example of another FFRDC that plays a role in the security community is the Software Engineering Institute (SEI) at Carnegie Mellon University, of which the CERT Coordination Center is a part.

E4. Why is MITRE maintaining CVE, and how long does MITRE plan to maintain it?

In accordance with its mission, MITRE has traditionally acted in the public interest. Its unique role allows it to provide an objective perspective to this effort. MITRE will maintain CVE as long as it serves the community to do so.

E5. Who pays for CVE? Who are the Sponsors?

Current and past sponsors are listed on the Sponsors page. Also see E6. What is the relationship between CVE and DHS?

E6. What is the relationship between CVE and DHS?

CVE is sponsored by the National Cyber Security Division (NCSD) at the U.S. Department of Homeland Security. US-CERT is the operational arm of the NCSD. US-CERT incorporates CVE Identifiers into its security advisories whenever possible and advocates the use of CVE and CVE-compatible products and services to the U.S. government and all members of the information security community.