EUVD-2026-17552CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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Description
Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, when the hidden prioritize_full_name_in_ux site setting is enabled (defaults to false, requires console access to change), user and group display names are rendered without HTML escaping in several assignment-related UI paths. This allows users with assign permission to inject arbitrary HTML/JavaScript that executes in the browser of any user viewing an affected topic. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.
Analysis
Stored cross-site scripting (XSS) in Discourse assignment UI allows authenticated users with assign permission to inject arbitrary HTML/JavaScript into user and group display names when the hidden prioritize_full_name_in_ux site setting is enabled, affecting versions 2026.1.0–2026.1.2, 2026.2.0–2026.2.1, and 2026.3.0. The injected payload executes in the browser of any user viewing an affected topic, enabling session hijacking, credential theft, or malware distribution. …
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