Vulnerability Description
Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.format_for_email because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and hashtag data-slug values can cause decoded attribute text to be reinterpreted as HTML. The vulnerable conversion also fails to strictly validate the Vimeo iframe host and path, allowing non-Vimeo allowlisted iframes to be converted. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/discourse/discourse/commit/234ee88a5b9b53bf938c53351eab201303
- https://github.com/discourse/discourse/commit/4b639a52f47fb3d46093bece9df147e4e9
- https://github.com/discourse/discourse/commit/a5d3b112d598242c1d1803d5a77bf98d5f
- https://github.com/discourse/discourse/commit/b25a074b165253e01fc4c8911b980fc683
- https://github.com/discourse/discourse/pull/42244
- https://github.com/discourse/discourse/pull/42245
- https://github.com/discourse/discourse/pull/42246
- https://github.com/discourse/discourse/pull/42247
- https://github.com/discourse/discourse/security/advisories/GHSA-3q6f-6gm9-m35v
FAQ
What is CVE-2026-72720?
CVE-2026-72720 is a vulnerability with a CVSS score of 6.4 (MEDIUM). Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.format_for_email because cooked attribute valu...
How severe is CVE-2026-72720?
CVE-2026-72720 has been rated MEDIUM with a CVSS base score of 6.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-72720?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.