CVE-2021-21660

Name: CVE-2021-21660
Creator: NVD / NIST
Published: 2021-05-25T17:15:08.15+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 1.09%

Last modified Jun 17, 2026

CVE-2021-21660 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. Jenkins Markdown Formatter Plugin 0.1.0 and earlier does not sanitize crafted link target URLs, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with the ability to edit any description rendered using the configured markup formatter.. EPSS estimates a 1.09% chance of exploitation in the next 30 days.

Description

Jenkins Markdown Formatter Plugin 0.1.0 and earlier does not sanitize crafted link target URLs, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with the ability to edit any description rendered using the configured markup formatter.

Metrics

CVSS 3.1

5.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

1.09%

61.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Jenkins	Markdown Formatter	<= 0.1.0

References

http://www.openwall.com/lists/oss-security/2021/05/25/3Mailing List, Third Party Advisory
https://www.jenkins.io/security/advisory/2021-05-25/#SECURITY-2198Vendor Advisory
https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-21660Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/25/3Mailing List, Third Party Advisory
https://www.jenkins.io/security/advisory/2021-05-25/#SECURITY-2198Vendor Advisory
https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-21660Third Party Advisory

Timeline

Published: May 25, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21660?

How severe is CVE-2021-21660?

CVE-2021-21660 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 1.09% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21660?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21660?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST