Description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, SiteSerializer.anonymous_default_navigation_menu_tags serializes tags from SiteSetting.default_navigation_menu_tags without applying DiscourseTagging.filter_visible for the anonymous viewer. An unauthenticated user can retrieve restricted tag names and descriptions through /site.json when those tags are limited by inaccessible categories, category tag groups, or tag-group permissions. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
References9
- github.com/discourse/discourse/commit/0248e9ca82d0493037a9ca04d…
- github.com/discourse/discourse/commit/03444ddb74d535dda557350f4…
- github.com/discourse/discourse/commit/900f51c147913f667e64484c2…
- github.com/discourse/discourse/commit/da84c677213cac3b024e753f1…
- github.com/discourse/discourse/pull/42091
- github.com/discourse/discourse/pull/42092
- github.com/discourse/discourse/pull/42093
- github.com/discourse/discourse/pull/42094
- github.com/discourse/discourse/security/advisories/GHSA-4p6q-h7…
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - EPSS — exploit probability
- 1% percentile: 45 · as of 12 November 2026
- CWE
- CWE-862
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.