What’s Vulnerable › Vulnerabilities

CVE-2021-21686

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.0% 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

File path filters in the agent-to-controller security subsystem of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories.

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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