AssemblaApplication · Jenkins
CVE-2026-57303
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 Assembla Plugin 1.4 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks, allowing attackers able to control the responses of the configured Assembla server to extract secrets from the Jenkins controller or perform server-side request forgery.
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 Assembla Plugin versions 1.4 and earlier contains an XML External Entity (XXE) injection vulnerability due to its XML parser not being configured to disable external entity processing. When the plugin parses XML responses from the Assembla server, attackers who can control or manipulate those responses can inject malicious XML that references external entities, allowing extraction of sensitive data from the Jenkins controller or SSRF attacks.
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
AssemblaApplication
<= 1.4CVSS 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
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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 if Assembla plugin is installedNavigate to Jenkins > Manage Jenkins > Manage Plugins > Installed tab and search for Assembla. Alternatively, check for the plugin directory at $JENKINS_HOME/plugins/assembla/Affected if The Assembla plugin is not present in the installed plugins list
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Locate the installed plugin versionIn the Jenkins UI Manage Plugins > Installed tab, locate the Assembla plugin and record the Version shown. If using CLI, run: java -jar jenkins-cli.jar -s http://[jenkins-url] list-plugins AssemblaAffected if Cannot determine version from UI or plugin directory is missing
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Compare version against affected rangeIf Assembla plugin version is found, compare it to the affected range: versions 1.4 and earlier are vulnerable. Version 1.5 and later contain the fix.Affected if Installed version is 1.4 or earlier (for example: 1.4, 1.3, 1.2, 1.1, 1.0)
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Confirm XML parsing configuration (optional validation)If source code access is available, inspect the plugin XML parsing code for DocumentBuilderFactory or SAXParserFactory configuration to verify external entity processing is disabledAffected if Parser configuration allows external entity processing (XXE-vulnerable pattern detected)
A Jenkins instance is affected if the Assembla plugin version is 1.4 or earlier, as this version range contains the XXE-vulnerable XML parser configuration.
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 the Assembla Plugin to version 1.5 or later, which configures the XML parser to prevent XXE attacks. If immediate upgrading is not possible, restrict network access to trusted Assembla servers only.
Fix this in Assembla
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-57303 — 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-2026-57303 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
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