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JenkinsApplication

CVE-2021-21683

MEDIUM · 6.5 CVSS v3.1 Published 2021-10-06
Fix available
A fix is available. Upgrade to after 2.314 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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
The file browser in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier may interpret some paths to files as absolute on Windows, resulting in a path traversal vulnerability allowing attackers with Overall/Read permission (Windows controller) or Job/Workspace permission (Windows agents) to obtain the contents of arbitrary files.

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

The Jenkins file browser in versions 2.314 and earlier (LTS 2.303.1 and earlier) contains a path traversal vulnerability on Windows systems where certain paths are incorrectly interpreted as absolute paths, allowing attackers with Overall/Read permission on Windows controllers or Job/Workspace permission on Windows agents to read arbitrary files on the system.

MitigationUpgrade Jenkins to a version newer than 2.314 (or LTS newer than 2.303.1). If immediate patching is not possible, restrict file browser access and monitor for suspicious path traversal attempts in file browser requests.

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:<= 2.303.1<= 2.314

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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. Check installed Jenkins version
    Navigate to Manage Jenkins > About Jenkins or run 'java -jar jenkins.war --version' from the Jenkins installation directory. The version is displayed on the main page footer in the web UI.
    Affected if Version is 2.314 or earlier, or LTS 2.303.1 or earlier
  2. Confirm Windows operating system
    Check the operating system where Jenkins controller or agent is running. Run 'systeminfo' on Windows or check system properties. The vulnerability only affects Windows systems.
    Affected if The Jenkins controller or the agent with accessible workspace runs on Windows
  3. Verify file browser access permissions
    Check if users have Overall/Read permission (for controller file browser) or Job/Configure permission on jobs with workspace access (for agent file browser). Review user permissions in Manage Jenkins > Manage Users and check job configurations.
    Affected if Users with Overall/Read or Job/Workspace permissions exist in the system
  4. Check if file browser feature is accessible
    Attempt to access the file browser: for controller, go to Manage Jenkins > Browse Files. For agent workspaces, navigate to a job > Workspace > Workspace browser link. Alternatively, check if any jobs have workspace directories configured.
    Affected if File browser functionality is accessible to non-admin users with read permissions

A user is affected if running Jenkins version 2.314 or earlier (or LTS 2.303.1 or earlier) on Windows, with users having Overall/Read or Job/Workspace permissions, and the file browser feature is accessible to them.

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 2.314
Interim mitigation

Upgrade Jenkins to a version newer than 2.314 (or LTS newer than 2.303.1). If immediate patching is not possible, restrict file browser access and monitor for suspicious path traversal attempts in file browser requests.

Recommended fix High confidence

Jenkins 2.315 (weekly) or Jenkins LTS 2.303.2

  1. Identify the current Jenkins version running in your environment
  2. Determine if you are using a weekly release or LTS release
  3. For weekly releases: Upgrade from Jenkins 2.314 or earlier to Jenkins 2.315 or later
  4. For LTS releases: Upgrade from Jenkins 2.303.1 or earlier to Jenkins 2.303.2 or later LTS
  5. Download the new Jenkins WAR file or use your package manager to perform the upgrade
  6. Restart Jenkins service to apply the changes
  7. Verify the upgrade was successful by checking the Jenkins version in the UI (Manage Jenkins > About Jenkins)
  8. Test that the file browser functionality works correctly after the upgrade
Caveat Standard Jenkins upgrade - review release notes for any behavior changes, but no specific breaking changes for this security fix

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

Fix this in Jenkins Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

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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-2021-21683 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