How severe is CVE-2021-21689?

CVE-2021-21689 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-21689 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21689?

CVE-2021-21689 primarily affects Jenkins. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21689?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-21689 published?

CVE-2021-21689 was published on 2021-11-04 and last updated on 2026-06-17.

CVE-2021-21689

CVE-2021-21689 is a critical-severity vulnerability in Jenkins with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Jenkins
Published: 2021-11-04
Last modified: 2026-06-17

Description

FilePath#unzip and FilePath#untar were not subject to any agent-to-controller access control in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

Frequently asked questions

What is CVE-2021-21689?: FilePath#unzip and FilePath#untar were not subject to any agent-to-controller access control in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.
How severe is CVE-2021-21689?: CVE-2021-21689 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-21689 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21689?: CVE-2021-21689 primarily affects Jenkins. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21689?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21689 published?: CVE-2021-21689 was published on 2021-11-04 and last updated on 2026-06-17.

References

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

Affected products (2)

cpe:2.3:a:jenkins:jenkins:*:*:*:*:lts:*:*:*
cpe:2.3:a:jenkins:jenkins:*:*:*:*:-:*:*:*

More vulnerabilities in Jenkins

CVE-2024-23897 — Critical (CVSS 9.8): Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable a feature of its CLI command parser that replaces…
CVE-2021-21696 — Critical (CVSS 9.8): Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not limit agent read/write access to the libs/ directory inside…
CVE-2021-21694 — Critical (CVSS 9.8): FilePath#toURI, FilePath#hasSymlink, FilePath#absolutize, FilePath#isDescendant, and FilePath#get*DiskSpace do not…
CVE-2021-21693 — Critical (CVSS 9.8): When creating temporary files, agent-to-controller access to create those files is only checked after they've been…
CVE-2021-21692 — Critical (CVSS 9.8): FilePath#renameTo and FilePath#moveAllChildrenTo in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier only check…
CVE-2021-21691 — Critical (CVSS 9.8): Creating symbolic links is possible without the 'symlink' agent-to-controller access control permission in Jenkins…

All CVEs affecting Jenkins →