What is CVE-2021-21648?

CVE-2021-21648 is a medium-severity vulnerability in Jenkins Credentials, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-05-11.

How severe is CVE-2021-21648?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2021-21648 known to be exploited?

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

XSS in Jenkins Credentials

CVE-2021-21648

Jenkins Credentials Plugin 2.3.18 and earlier does not escape user-controlled information on a view it provides, resulting in a reflected cross-site scripting (XSS) vulnerability.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-05-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.113 (96.0th percentile), scored 2026-10-29.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 96.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.113 · newest: 0.113 · change: 0.000

Affected products

Jenkins Credentials
Jenkins Project Credentials Plugin — versions unspecified, 2.3.0.1, 2.3.7.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

www.jenkins.io/security/advisory/2021-05-11/ (Vendor Advisory)

Frequently asked questions

What is CVE-2021-21648?: CVE-2021-21648 is a medium-severity vulnerability in Jenkins Credentials, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-05-11.
How severe is CVE-2021-21648?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-21648 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.