Support CoreApplication · Jenkins
CVE-2021-21621
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 Support Core Plugin 2.72 and earlier provides the serialized user authentication as part of the "About user (basic authentication details only)" information, which can include the session ID of the user creating the support bundle in some configurations.
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 Support Core Plugin versions 2.72 and earlier inadvertently includes serialized user authentication data within 'About user' support bundle information. In certain configurations, this serialized data can expose user session IDs, leading to session hijacking or impersonation risks.
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
Support CoreApplication
<= 2.72CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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 checksWork through these to decide whether this CVE applies to you.
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Check Support Core Plugin versionNavigate to Manage Jenkins > Manage Plugins > Installed tab and locate the Support Core Plugin to view its version number, or use the Jenkins CLI: java -jar jenkins-cli.jar list-plugins | grep "support-core"Affected if The installed version is 2.72 or earlier (any version <= 2.72)
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Verify if support bundle generation is accessibleCheck if users with Overall/Read or Overall/Administer permissions can access the support bundle feature via Manage Jenkins > Support Bundle or /support/ API endpointsAffected if The support bundle feature is accessible to non-admin users or users other than trusted administrators
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Inspect recent support bundle contentsIf available, examine any recently generated support bundles (found in $JENKINS_HOME/support/ or downloaded bundles) and look for files containing 'About user' or serialized authentication dataAffected if The bundle contains user session data, serialized authentication tokens, or session IDs in 'About user' information
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Review user session exposure riskCheck the support bundle manifest or logs for references to 'session', 'authentication', or serialized Java objects in user-related filesAffected if Serialized user session or authentication data is present in the support bundle output
A user is affected if they run Support Core Plugin version 2.72 or earlier AND have support bundle generation accessible to users who should not see sensitive session data.
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 dataUpdate Jenkins Support Core Plugin to version 2.73 or later. Until patching is possible, restrict access to the support bundle generation feature to only trusted administrators.
Fix this in Support Core
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 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 $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21621 — 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-2021-21621 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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