What is CVE-2021-21602?

CVE-2021-21602 is a medium-severity vulnerability in Jenkins, classified under Improper Link Resolution Before File Access. CVSS score: 6.5/10. Published 2021-01-13.

How severe is CVE-2021-21602?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2021-21602 known to be exploited?

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

Vulnerability in Jenkins

CVE-2021-21602

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows reading arbitrary files using the file browser for workspaces and archived artifacts by following symlinks.

Published 2021-01-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.022 (82.0th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 82.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000

Affected products

Jenkins
Jenkins Project — versions unspecified

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

www.jenkins.io/security/advisory/2021-01-13/ (Vendor Advisory)

Frequently asked questions

What is CVE-2021-21602?: CVE-2021-21602 is a medium-severity vulnerability in Jenkins, classified under Improper Link Resolution Before File Access. CVSS score: 6.5/10. Published 2021-01-13.
How severe is CVE-2021-21602?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-21602 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.