CVE-2026-47264
Discourse: Don't leak restricted tag group names via tag info
Description
Discourse is an open-source discussion platform. From versions 2026.1.0 to before 2026.1.4, 2026.3.0 to before 2026.3.1, and 2026.4.0 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.
How to fix CVE-2026-47264
To remediate CVE-2026-47264, upgrade the affected package to a fixed version below.
- —upgrade to 2026.1.4 or later
Is CVE-2026-47264 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 2026.1.0, < 2026.1.4, >= 2026.3.0, < 2026.3.1, >= 2026.4.0, < 2026.4.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |