What is CVE-2021-21615?

CVE-2021-21615 is a medium-severity vulnerability in Jenkins, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.3/10. Published 2021-01-26.

How severe is CVE-2021-21615?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Jenkins

CVE-2021-21615

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

Published 2021-01-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.009 (58.1th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Jenkins
Jenkins Project — versions 2.275, LTS 2.263.2

Weakness classification (CWE)

CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition

References

www.jenkins.io/security/advisory/2021-01-26/ (Vendor Advisory)
www.openwall.com/lists/oss-security/2021/01/26/2 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21615?: CVE-2021-21615 is a medium-severity vulnerability in Jenkins, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.3/10. Published 2021-01-26.
How severe is CVE-2021-21615?: Medium severity. CVSS v3 base score is 5.3 out of 10.