Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest Review Queue Interface cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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4.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest. It has been declared as problematic. Affected by this vulnerability is an unknown functionality of the component Review Queue Interface. Executing a manipulation can lead to cross site scripting. This vulnerability appears as CVE-2026-27740. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest and classified as problematic. This vulnerability affects some unknown processing of the component Review Queue Interface. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-27740 since 02/23/2026. The exploitation appears to be easy. The attack can be initiated remotely. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 2026.1.2 or 2026.2.1 eliminates this vulnerability. Applying the patch 44b84439df7e4424b2e7f216fd8fdd7dacff2227 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.7

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.1
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Discourse 2026.1.2/2026.2.1
Patch: 44b84439df7e4424b2e7f216fd8fdd7dacff2227

Timelineinfo

02/23/2026 CVE reserved
03/20/2026 +25 days Advisory disclosed
03/20/2026 +0 days VulDB entry created
03/25/2026 +5 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-95hc-42c6-wvvr
Status: Confirmed

CVE: CVE-2026-27740 (🔒)
GCVE (CVE): GCVE-0-2026-27740
GCVE (VulDB): GCVE-100-351868

Entryinfo

Created: 03/20/2026 07:46
Updated: 03/25/2026 02:04
Changes: 03/20/2026 07:46 (70), 03/24/2026 10:51 (1), 03/25/2026 02:04 (11)
Complete: 🔍
Cache ID: 216::103

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