CVE-2021-37633

Name: CVE-2021-37633
Creator: NVD / NIST
Published: 2021-08-09T20:15:07.597+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.76%

Last modified Jun 17, 2026

CVE-2021-37633 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Discourse is an open source discussion platform. In versions prior to 2.7.8 rendering of d-popover tooltips can be susceptible to XSS attacks. EPSS estimates a 0.76% chance of exploitation in the next 30 days.

Description

Discourse is an open source discussion platform. In versions prior to 2.7.8 rendering of d-popover tooltips can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. This issue is patched in the latest `stable` 2.7.8 version of Discourse. As a workaround users may ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

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

0.76%

50.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Discourse	Discourse	< 2.7.8	—
Discourse	Discourse	2.8.0	Beta2

References

https://github.com/discourse/discourse/commit/38199424bc840d2ef002cd1e9bffdbb99191eb47Patch, Third Party Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-v3v8-3m5w-pjp9Third Party Advisory
https://github.com/discourse/discourse/commit/38199424bc840d2ef002cd1e9bffdbb99191eb47Patch, Third Party Advisory
https://github.com/discourse/discourse/security/advisories/GHSA-v3v8-3m5w-pjp9Third Party Advisory

Timeline

Published: Aug 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-37633?

How severe is CVE-2021-37633?

CVE-2021-37633 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.76% probability of exploitation in the next 30 days.

How do I fix CVE-2021-37633?

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-2021-37633?

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

Scan your code now

Source: NVD / NIST