CVE-2021-21607 : Vulnerability Insights and Analysis

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier versions are affected by CVE-2021-21607. Attackers can exploit this vulnerability by manipulating query parameters in graph-rendering URLs to exhaust Jenkins' memory, potentially causing out-of-memory errors.

Understanding CVE-2021-21607

This section delves into the details of the CVE-2021-21607 vulnerability.

What is CVE-2021-21607?

CVE-2021-21607 affects Jenkins versions 2.274 and below, LTS 2.263.1 and earlier, allowing attackers to exploit memory allocation with excessive size value (CWE-789).

The Impact of CVE-2021-21607

The impact of this vulnerability is the potential exhaustion of available memory in Jenkins systems due to unbounded sizes in query parameters, leading to denial of service through out-of-memory errors.

Technical Details of CVE-2021-21607

This section covers the technical aspects of CVE-2021-21607.

Vulnerability Description

Jenkins versions 2.274 and below, LTS 2.263.1 and earlier fail to restrict query parameter sizes in graph-rendering URLs, enabling attackers to create URLs that consume all memory resources.

Affected Systems and Versions

The CVE-2021-21607 vulnerability impacts all instances running Jenkins 2.274 and below, LTS 2.263.1 and earlier versions.

Exploitation Mechanism

Attackers exploit this vulnerability by crafting URLs with large query parameter sizes, causing Jenkins to utilize excessive memory and trigger out-of-memory errors.

Mitigation and Prevention

This section provides insights on mitigating and preventing CVE-2021-21607.

Immediate Steps to Take

Immediate actions include updating Jenkins to a patched version, monitoring memory usage, and restricting network access to Jenkins instances.

Long-Term Security Practices

Implementing secure coding practices, conducting regular security audits, and educating users on safe URL handling can prevent similar vulnerabilities.

Patching and Updates

Regularly apply security patches, stay informed about Jenkins security advisories, and follow best practices in system configuration to protect against CVE-2021-21607.