SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-27154

Editing a post of a malicious user would trigger an XSS.

LOW 1.3EPSS 0.15%

Does this matter?

Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0
1.3 LOWCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.15% probability · 5th percentile
CISA KEV
Not listed
Weakness
CWE-79
Affected
discourse/discourse
Source
security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.