What is CVE-2021-21604?

CVE-2021-21604 is a high-severity vulnerability in Jenkins, classified under Deserialization of Untrusted Data. CVSS score: 8.0/10. Published 2021-01-13.

How severe is CVE-2021-21604?

High severity. CVSS v3 base score is 8.0 out of 10.

Deserialization in Jenkins

CVE-2021-21604

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows attackers with permission to create or configure various objects to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects once discarded by an administrator.

Vulnerability class: Insecure Deserialization

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

CVSS v3 metric

CVSS v3 base score 8.0 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.017 (76.0th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 76.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.017 · newest: 0.017 · change: 0.000

Affected products

Jenkins
Jenkins Project — versions unspecified

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

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

Frequently asked questions

What is CVE-2021-21604?: CVE-2021-21604 is a high-severity vulnerability in Jenkins, classified under Deserialization of Untrusted Data. CVSS score: 8.0/10. Published 2021-01-13.
How severe is CVE-2021-21604?: High severity. CVSS v3 base score is 8.0 out of 10.