CVE-2021-21691

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-11-04 · updated 2026-06-17
Weakness: CWE-59

Description

Creating symbolic links is possible without the 'symlink' agent-to-controller access control permission in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

Affected products

Jenkins: before 2.303.3; before 2.319 — fixed in 2.303.3, 2.319

How to fix

Upgrade to a fixed version: Jenkins 2.303.3, 2.319. Check the vendor advisory for mitigations.

References

https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455
https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455

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