Agent-to-controller access control allows reading/writing most content of build directories in Jenkins

Exploitation

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

CVSS

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

EPSS

• CVE-2021-21697: 1.60% estimated exploitation activity in the next 30 days; percentile 75.84 (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.

Agents are allowed some limited access to files on the Jenkins controller file system. The directories agents are allowed to access in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier include the directories storing build-related information, intended to allow agents to store build-related metadata during build execution. As a consequence, this allows any agent to read and write the contents of any build directory stored in Jenkins with very few restrictions (build.xml and some Pipeline-related metadata). Jenkins 2.319, LTS 2.303.3 prevents agents from accessing contents of build directories unless it’s for builds currently running on the agent attempting to access the directory. Update Pipeline: Nodes and Processes to version 2.40 or newer for Jenkins to associate Pipeline node blocks with the agent they’re running on for this fix. If you are unable to immediately upgrade to Jenkins 2.319, LTS 2.303.3, you can install the Remoting Security Workaround Plugin. It will prevent all…

Published by the source

24 May 2022, 19:19 UTC

Last modified by the source

18 Dec 2023, 11:30 UTC

Source last checked

26 Oct 2026, 16:21 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cv2w-q8c3-xjv7

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# Patch Next advisory brief: CVE-2021-21697

Advisory: Agent-to-controller access control allows reading/writing most content of build directories in Jenkins
IDs: CVE-2021-21697, GHSA-cv2w-q8c3-xjv7
Record: https://patchnext.com/advisories/cve-2021-21697 (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: Critical (CVSS 9.1)
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.main:jenkins-core 2.319, 2.303.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.jenkins-ci.main:jenkins-core: affected >= 2.304, <= 2.318; <= 2.303.2; fixed in 2.319, 2.303.3

## Suggested inspection (read-only)
- Maven org.jenkins-ci.main:jenkins-core: 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.main:jenkins-core.
- 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-cv2w-q8c3-xjv7 (GitHub-reviewed advisory GHSA-cv2w-q8c3-xjv7 lists affected ranges: Maven org.jenkins-ci.main:jenkins-core >=2.304 =0 <=2.303.2)

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