What’s Vulnerable › Vulnerabilities
CVE-2026-47264: Discourse: Don't leak restricted tag group names via tag info
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-12 · updated 2026-06-17
- Weakness: CWE-200
Description
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 products
- discourse: before 2026.1.0; from 2026.1.0 before 2026.1.4; from 2026.3.0 before 2026.3.1; from 2026.4.0 before 2026.4.1; 2026.5.0 — fixed in 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1
How to fix
Upgrade to a fixed version: discourse 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1. Check the vendor advisory for mitigations.
References
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