CVE-2026-27570
MEDIUMDiscourse Vulnerable to Stored XSS via Shared AI Conversation Onebox
Title source: cnaDescription
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox method in the SharedAiConversation model renders the conversation title directly into HTML without proper sanitization. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, tighten access by changing the `ai_bot_public_sharing_allowed_groups` site setting.
References (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv
X_Refsource_Misc x_refsource_misc
https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1
X_Refsource_Misc x_refsource_misc
https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1
X_Refsource_Misc x_refsource_misc
https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc
Scores
CVSS v3
6.1
EPSS
0.0035
EPSS Percentile
26.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-79
Status
published
Products (5)
discourse/discourse
2026.3.0
discourse/discourse
2026.1.0 - 2026.1.2
discourse/discourse
= 2026.3.0-latest
discourse/discourse
>= 2026.1.0-latest, < 2026.1.2
discourse/discourse
>= 2026.2.0-latest, < 2026.2.1
Published
Mar 19, 2026
Tracked Since
Mar 20, 2026