CVE-2021-41095

Name: CVE-2021-41095
Creator: NVD / NIST
Published: 2021-09-27T20:15:07.267+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2021-41095 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Discourse is an open source discussion platform. There is a cross-site scripting (XSS) vulnerability in versions 2.7.7 and earlier of the `stable` branch, versions 2.8.0.beta6 and earlier of the `beta` branch, and versions 2.8.0.beta6 and earlier of the `tests-passed` branch. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

Discourse is an open source discussion platform. There is a cross-site scripting (XSS) vulnerability in versions 2.7.7 and earlier of the `stable` branch, versions 2.8.0.beta6 and earlier of the `beta` branch, and versions 2.8.0.beta6 and earlier of the `tests-passed` branch. Rendering of some error messages that contain user input can be susceptible to XSS attacks. This vulnerability only affects sites which have blocked watched words that contain HTML tags, modified or disabled Discourse's default Content Security Policy. This issue is patched in the latest `stable`, `beta` and `tests-passed` versions of Discourse. As a workaround, avoid modifying or disabling Discourse’s default Content Security Policy, and blocking watched words containing HTML tags.

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

0.56%

42.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Discourse	Discourse	<= 2.7.7	—
Discourse	Discourse	2.8.0	Beta1

References

https://github.com/discourse/discourse/pull/14434/commits/40b776b9d39c41d9273d01eecf8fe03aa39fcb59Patch, Third Party Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-qvqx-2h7w-m479Third Party Advisory
https://github.com/discourse/discourse/pull/14434/commits/40b776b9d39c41d9273d01eecf8fe03aa39fcb59Patch, Third Party Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-qvqx-2h7w-m479Third Party Advisory

Timeline

Published: Sep 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-41095?

How severe is CVE-2021-41095?

CVE-2021-41095 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2021-41095?

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-2021-41095?

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

Scan your code now

Source: NVD / NIST