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JenkinsApplication

CVE-2021-21690

CRITICAL · 9.8 CVSS v3.1 Published 2021-11-04
Fix available
A fix is available. Upgrade to 2.303.3 / 2.319 or later.
See remediation →
100/100
Remediation priority · Urgent
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
Agent processes are able to completely bypass file path filtering by wrapping the file operation in an agent file path in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

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

This is an authorization bypass vulnerability in Jenkins where agent processes can completely circumvent file path filtering by wrapping file operations inside an agent file path. This allows unauthorized file system access on the Jenkins controller through agent-side operations.

MitigationUpgrade Jenkins to version 2.319 or later (LTS 2.303.3 or later) which contains the patched code. Prior to upgrade, test in a non-production environment to ensure plugin compatibility.

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
JenkinsApplication
Affected:< 2.303.3< 2.319

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
High
Integrity
High
Availability
High

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

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. Check installed Jenkins version
    Navigate to Manage Jenkins > About Jenkins or run: java -jar jenkins.war --version or check /var/lib/jenkins/war.xml
    Affected if Version is less than 2.319 (weekly) or less than 2.303.3 (LTS)
  2. Verify agent/agent connectivity is enabled
    Navigate to Manage Jenkins > Manage Nodes. Check if any agents (permanent or cloud) are configured and connected.
    Affected if Any agent nodes are configured and connected to the controller, as the vulnerability exploits agent-side operations to bypass controller file path restrictions
  3. Confirm file path filtering is in use
    Review Jenkins security settings under Manage Jenkins > Global Security. Look for agent-related security configurations or file access restrictions.
    Affected if File path filtering or security constraints for agent operations are configured (this is the protection being bypassed)
  4. Check agent-to-controller file access permissions
    Review agent-related permission settings in Configure Global Security, specifically any settings controlling agent process file system access to controller files.
    Affected if Agent processes are permitted file operations that could reach controller file system paths

A Jenkins installation is affected if its version is below 2.319 (weekly) or below 2.303.3 (LTS) AND agents are configured and connected, allowing agent processes to potentially bypass file path filtering on the controller.

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 2.303.3 / 2.319 or later
Fixed in 2.303.32.319
Interim mitigation

Upgrade Jenkins to version 2.319 or later (LTS 2.303.3 or later) which contains the patched code. Prior to upgrade, test in a non-production environment to ensure plugin compatibility.

Recommended fix High confidence

Jenkins 2.319 (weekly) or Jenkins 2.303.3 LTS

  1. 1. Back up your Jenkins home directory (JENKINS_HOME) including all configurations, jobs, and plugins
  2. 2. Check the current Jenkins version by navigating to Manage Jenkins > About Jenkins
  3. 3. Identify your release line: if using Weekly releases, plan for 2.319; if using LTS (Long Term Support), plan for 2.303.3
  4. 4. Stop the Jenkins service before upgrading
  5. 5. Download the WAR file or package for the target version (2.319 for weekly or 2.303.3 for LTS) from https://www.jenkins.io/download/
  6. 6. Replace the existing jenkins.war file or upgrade via your package manager (apt, yum, yum, Docker image, etc.)
  7. 7. Start the Jenkins service
  8. 8. After startup, verify the upgrade by checking Manage Jenkins > About Jenkins shows version 2.319 or 2.303.3
Caveat Review the Jenkins LTS upgrade guide at https://www.jenkins.io/doc/upgrade-guide/2.303/ for any behavior changes; minor plugin incompatibilities may occur

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

Fix this in Jenkins Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.

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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-2021-21690 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