JenkinsApplication
CVE-2021-21611
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 · uneditedJenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape display names and IDs of item types shown on the New Item page, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to specify display names or IDs of item types.
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 confidenceJenkins versions 2.274 and earlier, LTS 2.263.1 and earlier fail to properly escape display names and IDs of item types displayed on the New Item page. This allows attackers with the ability to specify item type names or IDs to inject malicious JavaScript code that executes in the browsers of other users viewing the page, resulting in a stored cross-site scripting (XSS) vulnerability.
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
<= 2.263.1<= 2.274CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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 command lineAffected if The version is 2.263.1 or earlier, or 2.274 or earlier (non-LTS)
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Verify user access to New Item pageCheck if any users or groups have the Overall/Administer permission or the Item/Create permission by reviewing Configure Global Security settingsAffected if Users other than administrators can access the New Item page and create or modify item types
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Review installed plugins that add item typesInspect the plugin manager at Manage Jenkins > Manage Plugins, looking for plugins that contribute custom item types (such as Pipeline, Freestyle project, or third-party plugins)Affected if Plugins that add custom item types are installed and users have permission to create items using those types
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Inspect item type display names for special charactersNavigate to the New Item page and view the list of available item types. Check if any item type names or descriptions contain HTML or JavaScript characters like <, >, ", or 'Affected if Any item type display name contains unescaped HTML/script characters that could be interpreted by the browser
The environment is affected if the Jenkins version is 2.263.1 or earlier (LTS) or 2.274 or earlier, AND users with permission to create items can access the New Item page.
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 Jenkins to version 2.274 or later, or LTS 2.263.2 or later, which includes proper escaping of item type display names and IDs. If immediate upgrade is not possible, restrict permissions for users who can create or modify item types.
Fix this in Jenkins
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21611 — 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-2021-21611 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
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