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MEDIUM severity

CVE-2021-21621 — support-core

MEDIUMFix: jenkinsci/support-core-plugin@9af9efa

CVE-2021-21621 is a medium-severity (CVSS 5.3) Information Exposure vulnerability in org.jenkins-ci.plugins:support-core. A fix is available for org.jenkins-ci.plugins:support-core — see the affected versions and patch details below.

Support bundles can include user session IDs in Jenkins Support Core Plugin

Also known asGHSA-92pg-8g57-hqpx
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs68th percentile — riskier than 68% of all scored CVEsHighest risk
0.00%0.57%1.14%1.71%0.0%1.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.jenkins-ci.plugins:support-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Support Core Plugin 2.72 and earlier provides the serialized user authentication as part of the "About user (basic authentication details only)" information (user.md).

In some configurations, this can include the session ID of the user creating the support bundle. Attackers with access to support bundle content and the Jenkins instance could use this information to impersonate the user who created the support bundle. Support Core Plugin 2.72.1 no longer provides the serialized user authentication as part of the "About user (basic authentication details only)" information.

As a workaround, deselecting "About user (basic authentication details only)" before creating a support bundle will exclude the affected information from the bundle.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.jenkins-ci.plugins:support-coreall versions2.72.1org.jenkins-ci.plugins:support-core:2.72.1

Affected Products

1 product · 1 configurations
Application
support corejenkins
≤ 2.72
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:support-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.jenkins-ci.plugins:support-core to 2.72.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21621 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

Support Core Plugin 2.72 and earlier provides the serialized user authentication as part of the \"About user (basic authentication details only)\" information (`user.md`). In some configurations, this can include the session ID of the user creating the support bundle. Attackers with access to support bundle content and the Jenkins instance could use this information to impersonate the user who created the support bundle. Support Core Plugin 2.72.1 no longer provides the serialized user authentication as part of the \"About user (basic authentication details only)\" information. As a workarou
O3 Security · Impact-Aware SCA

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CVE-2021-21621: support-core — Fixed in 2.72.1