How severe is CVE-2021-21685?

CVE-2021-21685 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-2021-21685 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21685?

CVE-2021-21685 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-2021-21685?

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-2021-21685 published?

CVE-2021-21685 was published on 2021-11-04 and last updated on 2026-06-17.

CVE-2021-21685

CVE-2021-21685 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. The underlying weakness is classified as CWE-862.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 1% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-862
Affected product: Jenkins
Published: 2021-11-04
Last modified: 2026-06-17

Description

Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not check agent-to-controller access to create parent directories in FilePath#mkdirs.

Frequently asked questions

What is CVE-2021-21685?: Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not check agent-to-controller access to create parent directories in FilePath#mkdirs.
How severe is CVE-2021-21685?: CVE-2021-21685 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-2021-21685 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21685?: CVE-2021-21685 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-2021-21685?: 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-2021-21685 published?: CVE-2021-21685 was published on 2021-11-04 and last updated on 2026-06-17.

References

Affected products (2)

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

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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…
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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…

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