CVE-2026-27154 PUBLISHED

Discourse has XSS when editing a malicious post

Assigner: GitHub_M
Reserved: 18.02.2026 Published: 26.02.2026 Updated: 26.02.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U
CVSS Score: 1.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	Low
Attack Complexity	Low	Integrity	None	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	discourse
Product	discourse
Versions	Version < 2025.12.2 is affected Version >= 2026.1.0-latest, < 2026.1.1 is affected Version >= 2026.2.0-latest, < 2026.2.0 is affected

References

https://github.com/discourse/discourse/security/advisories/GHSA-xv43-5gcp-wgw8

Problem Types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE