Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
https://github.com/discourse/discourse/security/advisories/GHSA-mwp7-572g-6qpx
https://github.com/discourse/discourse/releases/tag/v2026.6.0
https://github.com/discourse/discourse/releases/tag/v2026.5.1
https://github.com/discourse/discourse/releases/tag/v2026.4.2
https://github.com/discourse/discourse/releases/tag/v2026.1.5
Published: 2026-07-09
Updated: 2026-07-09
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Severity: Medium
Base Score: 6.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium