What is CVE-2021-21670?

CVE-2021-21670 is a medium-severity vulnerability in Jenkins. CVSS score: 4.3/10. Published 2021-06-30.

How severe is CVE-2021-21670?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Is CVE-2021-21670 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Jenkins

CVE-2021-21670

Jenkins 2.299 and earlier, LTS 2.289.1 and earlier allows users to cancel queue items and abort builds of jobs for which they have Item/Cancel permission even when they do not have Item/Read permission.

Published 2021-06-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.020 (80.4th percentile), scored 2026-10-03.

Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 80.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: +0.001

Affected products

Jenkins
Jenkins Project — versions unspecified

Public proof-of-concept exploits

References

www.jenkins.io/security/advisory/2021-06-30/ (Vendor Advisory)
www.openwall.com/lists/oss-security/2021/06/30/1 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21670?: CVE-2021-21670 is a medium-severity vulnerability in Jenkins. CVSS score: 4.3/10. Published 2021-06-30.
How severe is CVE-2021-21670?: Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2021-21670 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.