Incorrect permission checks in Jenkins Matrix Authorization Strategy Plugin may allow accessing some items

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2021-21623: 1.01% estimated exploitation activity in the next 30 days; percentile 63.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Items (like jobs) can be organized hierarchically in Jenkins, using the Folders Plugin or something similar. An item is expected to be accessible only if all its ancestors are accessible as well. Matrix Authorization Strategy Plugin 2.6.5 and earlier does not correctly perform permission checks to determine whether an item should be accessible. This allows attackers with Item/Read permission on nested items to access them, even if they lack Item/Read permission for parent folders.\n\nMatrix Authorization Strategy Plugin 2.6.6 requires Item/Read permission on parent items to grant Item/Read permission on an individual item. As a workaround in older releases, do not grant permissions on individual items to users who do not have access to parent items. In case of problems, the Java system property hudson.security.AuthorizationMatrixProperty.checkParentPermissions can be set to false, completely disabling this fix.

Published by the source

24 May 2022, 17:44 UTC

Last modified by the source

15 Dec 2023, 10:21 UTC

Source last checked

26 Oct 2026, 16:21 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-96jw-3xw4-mq9p

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# Patch Next advisory brief: CVE-2021-21623

Advisory: Incorrect permission checks in Jenkins Matrix Authorization Strategy Plugin may allow accessing some items
IDs: CVE-2021-21623, GHSA-96jw-3xw4-mq9p
Record: https://patchnext.com/advisories/cve-2021-21623 (revision 1, source checked 26 Oct 2026, 16:21 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.jenkins-ci.plugins:matrix-auth 2.6.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.jenkins-ci.plugins:matrix-auth: affected <= 2.6.5; fixed in 2.6.6

## Suggested inspection (read-only)
- Maven org.jenkins-ci.plugins:matrix-auth: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.jenkins-ci.plugins:matrix-auth.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-96jw-3xw4-mq9p (GitHub-reviewed advisory GHSA-96jw-3xw4-mq9p lists affected ranges: Maven org.jenkins-ci.plugins:matrix-auth >=0 <=2.6.5)

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