CVE-2026-27154
Received Received - Intake
Stored XSS in Discourse User Full Name Allows Post Editing Abuse

Publication date: 2026-02-26

Last updated on: 2026-03-02

Assigner: GitHub, Inc.

Description
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` => true; and `prioritize_username_in_ux` => false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
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Meta Information
Published
2026-02-26
Last Modified
2026-03-02
Generated
2026-06-16
AI Q&A
2026-02-27
EPSS Evaluated
2026-06-14
NVD
CVE-2026-27154
EUVD
EUVD-2026-8895
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
discourse discourse to 2025.12.2 (exc)
discourse discourse From 2026.1.0 (inc) to 2026.1.1 (exc)
discourse discourse 2026.2.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
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.
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Executive Summary

This vulnerability affects the Discourse open source discussion platform. Before certain fixed versions, a user's full name could be interpreted as raw HTML if specific settings were enabled: 'display_name_on_posts' set to true and 'prioritize_username_in_ux' set to false. This allowed a malicious user to inject HTML code, leading to a cross-site scripting (XSS) attack when their post was edited.

Impact Analysis

The vulnerability can lead to cross-site scripting (XSS) attacks, which may allow attackers to execute malicious scripts in the context of other users viewing or interacting with the platform. This can result in unauthorized actions, data theft, or session hijacking when a post by a malicious user is edited.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, upgrade Discourse to one of the patched versions: 2025.12.2, 2026.1.1, or 2026.2.0.

No known workarounds are available, so applying the update is the immediate and recommended step.

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