Filesystem TriggerApplication · Jenkins
CVE-2021-21657
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 Filesystem Trigger Plugin 0.40 and earlier does not configure its XML parser to prevent XML external entity (XXE) 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 confidenceThe Jenkins Filesystem Trigger Plugin versions 0.40 and earlier contains an XML External Entity (XXE) vulnerability due to its XML parser not being configured to prevent XXE attacks. An attacker could exploit this by supplying malicious XML files processed by the plugin, potentially leading to disclosure of local files or denial of service.
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
Filesystem TriggerApplication
<= 0.40CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Verify Filesystem Trigger Plugin is installedNavigate to Manage Jenkins > Manage Plugins > Installed tab, or list the contents of $JENKINS_HOME/plugins/ directory, and look for a plugin directory named 'filesystem-trigger' or similarAffected if The plugin directory exists in the plugins folder or appears in the Installed Plugins list
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Check the installed version of the Filesystem Trigger PluginIn the Jenkins plugin manager UI, locate the Filesystem Trigger Plugin and read the version column, or inspect the plugin manifest at $JENKINS_HOME/plugins/filesystem-trigger/META-INF/MANIFEST.MF for the Plugin-Version attributeAffected if The reported version is 0.40 or any version lower than 0.40
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Identify if the plugin is configured in any jobsReview Jenkins job configurations for the Filesystem Trigger build trigger, or search job config XML files in $JENKINS_HOME/jobs/ for the <fsTrigger> elementAffected if One or more jobs have the Filesystem Trigger enabled or configured
If the Filesystem Trigger Plugin is installed at version 0.40 or earlier and is actively configured in any Jenkins job, the environment is affected by this XXE vulnerability.
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 Filesystem Trigger Plugin to version 0.41 or later, which includes proper XML parser configuration to prevent XXE attacks.
Fix this in Filesystem Trigger
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 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 $2,464.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21657 — 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-2021-21657 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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- 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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