CVE-2026-27154
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
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| 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 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. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
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.
How can this vulnerability impact me? :
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.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
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.