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Github Branch SourceApplication · Jenkins

CVE-2024-23903

MEDIUM · 5.3 CVSS v3.1 Published 2024-01-24
Fix available
A fix is available. Upgrade to after 684.vea_fa_7c1e2fe3 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Jenkins GitLab Branch Source Plugin 684.vea_fa_7c1e2fe3 and earlier uses a non-constant time comparison function when checking whether the provided and expected webhook token are equal, potentially allowing attackers to use statistical methods to obtain a valid webhook token.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Jenkins GitLab Branch Source Plugin versions 684.vea_fa_7c1e2fe3 and earlier uses a non-constant time comparison function when validating webhook tokens, allowing attackers to exploit timing side-channels to statistically deduce valid tokens character-by-character through repeated webhook requests.

MitigationUpgrade to the patched version of Jenkins GitLab Branch Source Plugin that implements constant-time comparison for webhook token validation, or implement additional authentication layers around webhook endpoints as a compensating control.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Github Branch SourceApplication
Affected:<= 684.vea_fa_7c1e2fe3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify if GitLab Branch Source plugin is installed
    In Jenkins, go to Manage Jenkins > Manage Plugins > Installed tab and search for 'GitLab Branch Source' or check the plugin directory $JENKINS_HOME/plugins for gitlab-branch-source or gitlab-branch-source.hpi
    Affected if Plugin is installed and version is 684.vea_fa_7c1e2fe3 or earlier
  2. Confirm the installed plugin version
    In Jenkins plugin manager, locate the GitLab Branch Source plugin and note the version number from the installed plugins list or inspect the plugin manifest file
    Affected if Version number is less than or equal to 684.vea_fa_7c1e2fe3
  3. Check if webhooks are configured
    Review Jenkins jobs or folders that use GitLab Branch Source for webhook configuration. Look under job configuration > Branch Sources > GitLab configuration section, or inspect system configuration at Manage Jenkins > System > GitLab section
    Affected if Webhook endpoints are configured or enabled for GitLab integration
  4. Inspect webhook token settings
    Examine the webhook token configuration in the GitLab project settings or Jenkins job configuration under the 'GitLab' branch source settings, looking for explicitly set webhook tokens
    Affected if A webhook token is configured and the plugin version is vulnerable
  5. Review webhook request logs for timing anomalies
    Check Jenkins logs or web server access logs for repeated webhook requests from GitLab, noting if response times vary consistently with token character positions
    Affected if Webhook requests show statistically consistent timing patterns that could indicate token brute-force attempts

Your environment is affected if the GitLab Branch Source plugin version is 684.vea_fa_7c1e2fe3 or earlier and webhooks with tokens are configured in Jenkins.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 684.vea_fa_7c1e2fe3
Interim mitigation

Upgrade to the patched version of Jenkins GitLab Branch Source Plugin that implements constant-time comparison for webhook token validation, or implement additional authentication layers around webhook endpoints as a compensating control.

Recommended fix Moderate confidence

GitLab Branch Source Plugin version > 684.vea_fa_7c1e2fe3 (upgrade to latest available version)

  1. Navigate to Manage Jenkins > Manage Plugins
  2. Select the 'Updates' tab
  3. Locate 'GitLab Branch Source Plugin' in the list
  4. Click 'Update' to install the latest version
  5. Restart Jenkins if required to complete the installation
  6. Verify the plugin version is greater than 684.vea_fa_7c1e2fe3 under Manage Plugins > Installed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Github Branch Source Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,540
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-23903 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data