CVE-2024-21496

Name: CVE-2024-21496
Creator: NVD / NIST
Published: 2024-02-17T05:15:09.603+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.58%

Last modified Jun 17, 2026

CVE-2024-21496 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. All versions of the package github.com/greenpau/caddy-security are vulnerable to Cross-site Scripting (XSS) via the Referer header, due to improper input sanitization. Although the Referer header is sanitized by escaping some characters that can allow XSS (e.g., [&], [<], [>], ["], [']), it does not account for the attack based on the JavaScript URL scheme (e.g., javascript:alert(document.domain)// payload). EPSS estimates a 0.58% chance of exploitation in the next 30 days.

Description

All versions of the package github.com/greenpau/caddy-security are vulnerable to Cross-site Scripting (XSS) via the Referer header, due to improper input sanitization. Although the Referer header is sanitized by escaping some characters that can allow XSS (e.g., [&], [<], [>], ["], [']), it does not account for the attack based on the JavaScript URL scheme (e.g., javascript:alert(document.domain)// payload). Exploiting this vulnerability may not be trivial, but it could lead to the execution of malicious scripts in the context of the target user’s browser, compromising user sessions.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.58%

43.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Authcrunch	Caddy-Security	All versions

References

https://blog.trailofbits.com/2023/09/18/security-flaws-in-an-sso-plugin-for-caddy/Exploit, Third Party Advisory
https://github.com/greenpau/caddy-security/issues/267Exploit, Issue Tracking
https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMGREENPAUCADDYSECURITY-6249860Third Party Advisory
https://blog.trailofbits.com/2023/09/18/security-flaws-in-an-sso-plugin-for-caddy/Exploit, Third Party Advisory
https://github.com/greenpau/caddy-security/issues/267Exploit, Issue Tracking
https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMGREENPAUCADDYSECURITY-6249860Third Party Advisory

Timeline

Published: Feb 17, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2024-21496?

How severe is CVE-2024-21496?

CVE-2024-21496 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.

How do I fix CVE-2024-21496?

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-2024-21496?

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

Scan your code now

Source: NVD / NIST