JenkinsApplication
CVE-2020-2105
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 · uneditedREST API endpoints in Jenkins 2.218 and earlier, LTS 2.204.1 and earlier were vulnerable to clickjacking attacks.
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 confidenceREST API endpoints in Jenkins 2.218 and earlier lacked X-Frame-Options or Content-Security-Policy frame-ancestors protections, allowing them to be embedded in iframes on attacker-controlled pages. This enables clickjacking attacks where users can be tricked into performing unintended Jenkins actions through overlaid invisible or disguised interface elements.
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
<= 2.204.1<= 2.218CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Jenkins versionNavigate to Manage Jenkins > About Jenkins or run `java -jar jenkins.war --version` from the server. Alternatively, access the /api/json endpoint and check the 'version' field.Affected if The version is 2.218 or earlier, or 2.204.1 or earlier for LTS releases.
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Inspect HTTP response headers on REST API endpointsUse a browser dev tool or curl to request any REST API endpoint (e.g., /api/json, /job/{name}/api/json) and examine the response headers. Look specifically for X-Frame-Options and Content-Security-Policy headers.Affected if Neither X-Frame-Options (with DENY or SAMEORIGIN) nor Content-Security-Policy (with frame-ancestors directive) headers are present in the response.
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Verify if REST endpoints can be embedded in iframesCreate a test HTML page with an iframe src pointing to a Jenkins REST API endpoint (e.g., <iframe src='http://yourjenkins/api/json'>). Open this page in a browser and check if the content loads.Affected if The REST API endpoint content loads inside the iframe without being blocked by the browser's frame-breaking logic.
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Check servlet container header configurationExamine the underlying servlet container (Tomcat, Jetty, etc.) configuration files for X-Frame-Options or CSP header definitions. For embedded Jetty, check jenkins.xml or equivalent startup configuration.Affected if No frame-breaking headers are configured at the container level for REST API paths.
You are affected if your Jenkins version is 2.218 or earlier (or 2.204.1 or earlier for LTS) AND the REST API endpoints lack X-Frame-Options or Content-Security-Policy frame-ancestors headers, allowing them to be loaded in iframes on external sites.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade to Jenkins 2.219 or LTS 2.204.2 or later which implement proper frame-breaking protections, or configure the underlying servlet container to send X-Frame-Options: DENY or SAMEORIGIN headers for REST endpoints.
Fix this in Jenkins
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-2105 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-2105 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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