What is CVE-2021-21659?

CVE-2021-21659 is a high-severity vulnerability in Jenkins Urltrigger. CVSS score: 8.1/10. Published 2021-05-25.

How severe is CVE-2021-21659?

High severity. CVSS v3 base score is 8.1 out of 10.

Vulnerability in Jenkins Urltrigger

CVE-2021-21659

Jenkins URLTrigger Plugin 0.48 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

Published 2021-05-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.

EPSS exploit prediction

EPSS: 0.668 (99.3th percentile), scored 2026-10-29.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.668 · newest: 0.668 · change: 0.000

Affected products

Jenkins Urltrigger
Jenkins Project Urltrigger Plugin — versions unspecified

References

www.jenkins.io/security/advisory/2021-05-25/ (Vendor Advisory)
www.openwall.com/lists/oss-security/2021/05/25/3 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21659?: CVE-2021-21659 is a high-severity vulnerability in Jenkins Urltrigger. CVSS score: 8.1/10. Published 2021-05-25.
How severe is CVE-2021-21659?: High severity. CVSS v3 base score is 8.1 out of 10.