What is CVE-2021-21668?

CVE-2021-21668 is a medium-severity vulnerability in Jenkins Scriptler, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-06-16.

How severe is CVE-2021-21668?

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

Is CVE-2021-21668 known to be exploited?

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

XSS in Jenkins Scriptler

CVE-2021-21668

Jenkins Scriptler Plugin 3.1 and earlier does not escape script content, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Scriptler/Configure permission.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-06-16 · 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: 0.760 (99.5th percentile), scored 2026-10-28.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.760 · newest: 0.760 · change: 0.000

Affected products

Jenkins Scriptler
Jenkins Project Scriptler Plugin — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

www.jenkins.io/security/advisory/2021-06-16/ (Vendor Advisory)
www.openwall.com/lists/oss-security/2021/06/16/3 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21668?: CVE-2021-21668 is a medium-severity vulnerability in Jenkins Scriptler, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-06-16.
How severe is CVE-2021-21668?: Medium severity. CVSS v3 base score is 5.4 out of 10.
Is CVE-2021-21668 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.