What is CVE-2021-21618?

CVE-2021-21618 is a medium-severity vulnerability in Jenkins Repository Connector, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-24.

How severe is CVE-2021-21618?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Jenkins Repository Connector

CVE-2021-21618

Jenkins Repository Connector Plugin 2.0.2 and earlier does not escape parameter names and descriptions for past builds, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Item/Configure permission.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.795 (99.6th percentile), scored 2026-10-28.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.818 · newest: 0.795 · change: -0.023

Affected products

Jenkins Repository Connector
Jenkins Project Repository Connector Plugin — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.jenkins.io/security/advisory/2021-02-24/ (Vendor Advisory)

Frequently asked questions

What is CVE-2021-21618?: CVE-2021-21618 is a medium-severity vulnerability in Jenkins Repository Connector, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-24.
How severe is CVE-2021-21618?: Medium severity. CVSS v3 base score is 5.4 out of 10.