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

5.3MEDIUM

Key Information:

Vendor

Discourse
Status
Discourse
Vendor
CVE Published:
12 June 2026

What is CVE-2026-47264?

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 Version(s)

discourse >= 2026.1.0-latest, < 2026.1.4 < 2026.1.0-latest, 2026.1.4

discourse >= 2026.3.0-latest, < 2026.3.1 < 2026.3.0-latest, 2026.3.1

discourse >= 2026.4.0-latest, < 2026.4.1 < 2026.4.0-latest, 2026.4.1

References

https://github.com/discourse/discourse/security/advisorie...
x_refsource_CONFIRM

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.