How severe is CVE-2021-21693?

CVE-2021-21693 has a CVSS 3.x base score of 9.8, 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 high.

Is CVE-2021-21693 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21693?

CVE-2021-21693 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-2021-21693?

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-2021-21693 published?

CVE-2021-21693 was published on 2021-11-04 and last updated on 2026-06-17.

CVE-2021-21693

CVE-2021-21693 is a critical-severity vulnerability in Jenkins with a CVSS 3.x base score of 9.8. 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-863.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Jenkins
Published: 2021-11-04
Last modified: 2026-06-17

Description

When creating temporary files, agent-to-controller access to create those files is only checked after they've been created in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

Frequently asked questions

What is CVE-2021-21693?: When creating temporary files, agent-to-controller access to create those files is only checked after they've been created in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.
How severe is CVE-2021-21693?: CVE-2021-21693 has a CVSS 3.x base score of 9.8, 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 high.
Is CVE-2021-21693 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21693?: CVE-2021-21693 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-2021-21693?: 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-2021-21693 published?: CVE-2021-21693 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:*:*:*:*:-:*:*:*

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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-2021-21694 — Critical (CVSS 9.8): FilePath#toURI, FilePath#hasSymlink, FilePath#absolutize, FilePath#isDescendant, and FilePath#get*DiskSpace do not…
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…
CVE-2021-21690 — Critical (CVSS 9.8): Agent processes are able to completely bypass file path filtering by wrapping the file operation in an agent file path…

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