Common Vulnerabilities and Exposures (CVE)

Identifying and managing vulnerabilities effectively is one of the most crucial steps in reducing risk and maintaining effective protection from emerging threats. The Common Vulnerabilities and Exposures (CVE) program plays an essential role in this effort by providing a standardized identification system for vulnerabilities, enabling organizations worldwide to track and address threats consistently.

The CVE system was established in 1999 by MITRE Corporation, with the goal of creating a universal, standardized identifier for software vulnerabilities. For organizations, CVEs facilitate consistent tracking, reporting, and communication around vulnerabilities across different teams and security products. The CVE system ensures that the industry speaks a common language when discussing vulnerabilities, from security advisories to patching efforts.

The CVE Lifecycle
The lifecycle of a CVE entry spans several stages, from initial identification to eventual publication. Here’s a breakdown of each stage:

• Discover and Report: Vulnerabilities are identified by a wide range of sources, including independent security researchers, vendors, and even security-conscious individuals. Once a vulnerability is identified, a report is submitted to a CVE Numbering Authority (CNA) for assessment and processing.
• Assignment and Validation: CVE Numbering Authorities, or CNAs, are organizations authorized to assign CVE IDs to vulnerabilities within a specific scope, typically the organization’s own products. Once a vulnerability report is received, the CNA vets the report, and if necessary reserves a CVE ID for the new vulnerability.
  The vulnerability is then fully reviewed and validated, ensuring the scope of the vulnerability is properly understood. If the vulnerability is deemed not to have merit, the CVE ID will be marked as rejected. The CNA typically also begins development of a patch for the vulnerability, which can take some time depending on the nature of the vulnerability and the risk of in-the-wild exploitation.
• Submission and Publication: Once all the above steps are completed the CNA submits all relevant details through MITRE and the CVE record is published to the public CVE list. At this point the vulnerability is available to security vendors and organizations around the world.
• Enrichment: Published CVEs are imported into NIST’s National Vulnerability Database, where they are further enriched. NVD enrichment adds additional context including official designations for platforms that the vulnerability affects, category for the vulnerability, and standardized severity scores for the vulnerability. The time for this enrichment can vary significantly, depending on the availability of reference material as well as the CVE backlog at the time of publication.
• Exploitation: If evidence of active exploitation surfaces for a published CVE vulnerability, it’s important to communicate this to the security community to assist with prioritization of remediation efforts. CISA maintains the Known Exploited Vulnerabilities (KEV) list to serve this purpose. CISA relies on reports from a variety of community sources, as well as their own internal monitoring and open-source research. Once CISA is aware of a new exploitation, the KEV is typically updated within 24 hours, but it’s not uncommon for an exploit to be in use in-the-wild for days or weeks before a CISA notification.
• Updates: CVE records may be updated over time, as additional details become available, such as updated severity ratings or additional references. Updates are submitted through a similar process to the original CVE, and are validated by the relevant CNA.

What information is included in a CVE?
Once a CVE record is published and enriched via the NVD, it typically includes the following key pieces of information:

• CVE ID: A unique identifier for the vulnerability, following a standardized format like "CVE-YYYY-NNNNN," where “YYYY” represents the year the CVE ID was initially reserved, and “NNNNN” is a 5-digit identifier.
• Description: A concise summary of the vulnerability, including affected products and general information about the nature of the issue. The description provides enough information to identify the issue without delving into technical detail or exploit specifics.
• References: Links to additional resources, advisories, or vendor statements that provide further details about the vulnerability.
• Affected Products and Versions: A list of specific products, software versions, or platforms impacted by the vulnerability. This information is shared in Common Platform Enumeration (CPE) format, which provides an unambiguous, structured naming scheme for the affected products.
• Weakness Enumeration: Weakness enumeration helps organizations to understand the general class or nature of the vulnerability. Common Weakness Enumeration (CWE). is used to categorize the type of vulnerability (e.g., CWE-79 for cross-site scripting or CWE-89 for SQL injection).
• Severity and Scoring: CVE records include a severity score, usually in the form of a CVSS (Common Vulnerability Scoring System) rating provided by the NVD. The CVSS score gives a numerical rating for the severity of the vulnerability, helping teams prioritize based on factors like impact and exploitability.
• CISA KEV: If there are known in-the-wild exploits of a vulnerability, vulnerability is listed on CISA’s Known Exploited Vulnerabilities (KEV) list, and an appropriate note is appended to the CVE record..

Challenges in Using CVEs
Despite the essential role CVEs play, relying solely on CVE information can introduce several challenges in vulnerability management:

• Incompleteness and Delays: While the CVE database is extensive, it is not exhaustive. Many vulnerabilities go unlisted, often due to resource limitations or prioritization of high-impact vulnerabilities by CNAs. Additionally, delays in CVE assignment—especially with zero-day vulnerabilities—can leave organizations with a dangerous gap in their threat intelligence. These delays are exacerbated by the multiple parties involved in documenting a CVE, including the CNA, MITRE, NVD, and CISA.
• Data Quality and Consistency Issues: CVE entries can vary widely in the level of detail provided, with some entries offering minimal information. This inconsistency can create confusion when teams try to assess the risk posed by a vulnerability, as they may lack essential context to understand its true impact.
• Contextual Limitations: CVEs focus on providing identifiers and basic vulnerability details, but lack exploitability information that many organizations need to prioritize effectively. Knowing that a vulnerability exists is not always enough; teams need contextual details like exploit availability, threat actor activity, and environmental relevance to determine whether immediate action is warranted.
• Volume and Prioritization: With tens of thousands of CVEs published each year, the sheer volume can be overwhelming. Without additional context, security teams can struggle to identify which vulnerabilities are most critical to their environment, leading to a “patch everything” mindset that is neither efficient nor sustainable.

Conclusion
Understanding and utilizing the CVE system is essential for effective vulnerability management, but CVEs alone often do not provide the full picture. The challenges posed by CVE data—such as delays, lack of contextual detail, and overwhelming volume—highlight the need for supplemental intelligence that provides a deeper, more accurate perspective on vulnerabilities.

Solutions like VulnCheck enhance vulnerability data with critical exploit and threat intelligence in near real time, empowering organizations to prioritize vulnerabilities based on real-world risk. By augmenting CVE data with VulnCheck Exploit Intelligence, security teams can act faster and maintain a proactive approach in a rapidly-evolving threat landscape.