CVE-2026-27740
MEDIUM
5,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: passive
Confidentiality: N/A
Integrity: N/A
Availability: N/A
Description
AI Translation Available
Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a cross-site scripting vulnerability that arises because the system trusts the raw output from an AI Large Language Model (LLM) and renders it using htmlSafe in the Review Queue interface without adequate sanitization. A malicious attacker can use valid Prompt Injection techniques to force the AI to return a malicious payload (e.g., tags). When a Staff member (Admin/Moderator) views the flagged post in the Review Queue, the payload executes. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, temporarily disable AI triage automation scripts.
79
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
StableCommon Consequences
Security Scopes Affected:
Access Control
Confidentiality
Integrity
Availability
Potential Impacts:
Bypass Protection Mechanism
Read Application Data
Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies:
AI/ML, Web Based, Web Server
https://github.com/discourse/discourse/commit/44b84439df7e4424b2e7f216fd8fdd7da…
https://github.com/discourse/discourse/commit/8ae7cb2414d6918d7fc45e1fda7ffbb32…
https://github.com/discourse/discourse/commit/ed70949f2c047196f33cfa94f2819df29…
https://github.com/discourse/discourse/security/advisories/GHSA-95hc-42c6-wvvr