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CVE-2026-27740

MEDIUM

6.1

Description

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.

CVE Details

CVSS v3.1 Score6.1

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

Published3/19/2026

Last Modified3/25/2026

Sourcenvd

Honeypot Sightings0

Affected Products

discourse:discourse

Weaknesses (CWE)

CWE-79

References

https://github.com/discourse/discourse/commit/44b84439df7e4424b2e7f216fd8fdd7dacff2227(security-advisories@github.com)

https://github.com/discourse/discourse/commit/8ae7cb2414d6918d7fc45e1fda7ffbb32912a975(security-advisories@github.com)

https://github.com/discourse/discourse/commit/ed70949f2c047196f33cfa94f2819df29c5d1e5f(security-advisories@github.com)

https://github.com/discourse/discourse/security/advisories/GHSA-95hc-42c6-wvvr(security-advisories@github.com)

IOC Correlations

No correlations recorded

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