CVE-2026-47264 — Discourse: Don't leak restricted tag group names via tag info

Description (CNA)

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1, DetailedTagSerializer#tag_group_names returned every tag group a tag belonged to without filtering against the requesting user's visibility. With SiteSetting.tags_listed_by_group enabled, anonymous and unprivileged users hitting TagsController#info (which is exempt from requires_login) could read the names of tag groups restricted to specific user groups or non-visible categories. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

Affected (CNA)

Vendor / product	Versions
discourse / discourse	affected >= 2026.1.0-latest, < 2026.1.4; affected >= 2026.3.0-latest, < 2026.3.1; affected >= 2026.4.0-latest, < 2026.4.1

CWE

CWE-200

References

https://github.com/discourse/discourse/security/advisories/GHSA-4q5q-6hh6-53x2

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.