What is the CVSS score of CVE-2026-27570?

CVE-2026-27570 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Discourse are affected by CVE-2026-27570?

Organizations using Discourse should be aware of moderate risk from CVE-2026-27570, a cross-site scripting vulnerability rated CVSS 6.1.. A patch is available.

How to fix or mitigate CVE-2026-27570?

Within 30 days: Identify affected systems running the SharedAiConversation model renders the conversation titl and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Discourse CVE-2026-27570

EUVD-2026-13192 MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-03-19 GitHub_M

XSS Discourse

6.1

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.1 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Patch available

Apr 16, 2026 - 05:29 EUVD

2026.2.1,2026.1.2

EUVD ID Assigned

Mar 19, 2026 - 21:00 euvd

EUVD-2026-13192

Analysis Generated

Mar 19, 2026 - 21:00 vuln.today

CVE Published

Mar 19, 2026 - 20:52 nvd

MEDIUM 6.1

DescriptionGitHub Advisory

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.

AnalysisAI

Reflected cross-site scripting in Discourse AI conversation sharing allows unauthenticated attackers to inject malicious scripts through improperly sanitized conversation titles in the onebox rendering feature. An attacker can craft a malicious shared conversation link to execute arbitrary JavaScript in the context of other users' browsers, potentially stealing session tokens or performing unauthorized actions. The vulnerability affects versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, and currently has no patch available as a preventive measure.