Multiple Jenkins Vulnerabilities Allow Attackers to Expose Secrets

Jenkins, the widely-used open-source automation server, issued a high-priority security advisory on March 5, 2025, disclosing four medium-severity vulnerabilities affecting its core platform.

The flaws—tracked as CVE-2025-27622 through CVE-2025-27625—impact secrets management, cross-site request forgery (CSRF) protections, and URL validation.

Immediate upgrades to Jenkins 2.500 (weekly) or 2.492.2 (LTS) are recommended to mitigate risks.

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Exposure of Encrypted Secrets via API/CLI Access

Two vulnerabilities (CVE-2025-27622 and CVE-2025-27623) stemmed from improper redaction of encrypted secrets in agent and view configurations.

Attackers with Agent/Extended Read or View/Read permissions could exploit unpatched systems to access sensitive data stored in config.xml files via REST API or CLI endpoints.

Jenkins 2.499 and earlier, along with LTS 2.492.1 and earlier, failed to mask encrypted values—a regression from the 2016 SECURITY-266 fix.

The resolved versions now enforce role-based access controls, restricting decrypted secret visibility to users with Configure permissions.

CSRF and Open Redirect Vulnerabilities

A CSRF flaw (CVE-2025-27624) allowed unauthorized toggling of side panel widgets (e.g., Build Queue) via malicious HTTP requests.

Attackers could inject arbitrary panel IDs into user profiles, enabling persistent UI manipulation.

Concurrently, an open redirect issue (CVE-2025-27625) permitted phishing attacks by interpreting backslash-based URLs (e.g., \example.com) as valid redirects.

Browsers resolved these as scheme-relative paths, bypassing Jenkins’ URL safelist.

Patches enforce POST requests for sidepanel endpoints and reject backslash-initial redirects, aligning with OWASP CSRF prevention guidelines and RFC 3986 URI normalization standards.

Remediation and Upgrade Recommendations

Affected versions include Jenkins weekly ≤2.499 and LTS ≤2.492.1. The fixes—rolled out in 2.500 (weekly) and 2.492.2 (LTS)—introduce:

• Enhanced secret redaction for REST/CLI interfaces
• Stricter HTTP method enforcement
• Redirect path validation using regex-based safelists

Administrators should prioritize upgrades and audit user permissions, particularly for roles with Read-only access.

For environments requiring delayed patches, temporary mitigations include revoking unnecessary permissions and implementing reverse proxy rules to block malicious redirect patterns.

Jenkins emphasized these updates as part of its quarterly security hardening cycle, underscoring the importance of continuous dependency scanning in CI/CD pipelines.

With CVSS scores averaging 6.5, proactive remediation is critical to prevent credential exfiltration and session hijacking in DevOps workflows.

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