Home/CVE/Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox
CVE

CVE-2026-27570

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox

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.

MEDIUM · CVSS 6.1 EPSS 0.00018
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
▤

Affected Products & Versions

3
discourse>= 2026.1.0 and < 2026.1.2
discourse>= 2026.2.0 and < 2026.2.1
discourseall versions
▣

Scoring & Timeline

6.1
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD19 Mar 2026 · 09:17 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1Patch
https://github.com/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1Patch
https://github.com/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088ccPatch
https://github.com/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmvVendor Advisory
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