Jenkins GitLab Branch Source Plugin 684.vea_fa_7c1e2fe3 and earlier does not use a constant-time comparison function when checking whether the provided and expected webhook token are equal.

This could potentially allow attackers to use statistical methods to obtain a valid webhook token.

GitLab Branch Source Plugin 688.v5fa_356ee8520 uses a constant-time comparison function when validating the webhook token.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-23903
• https://www.jenkins.io/security/advisory/2024-01-24/#SECURITY-2871
• http://www.openwall.com/lists/oss-security/2024/01/24/6
• jenkinsci/gitlab-branch-source-plugin@8bfe104