CVE-2026-72728: Discourse

Medium severity, CVSS 6.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Discourse is an open-source discussion platform. Prior to 2026.1.7, an authenticated user could submit specially formed URLs that bypassed the Onebox allowlist and embedded malicious content in a site. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1.

Affected products

• Discourse Discourse: before 2026.1.7 (fixed in 2026.1.7); from 2026.6.0-latest, before 2026.6.2 (fixed in 2026.6.2); from 2026.7.0-latest, before 2026.7.1 (fixed in 2026.7.1); from 2026.8.0-latest, before 2026.8.0-latest.1 (fixed in 2026.8.0-latest.1)

Published 2026-08-10. Last modified 2026-09-08.