What’s Vulnerable › Vulnerabilities

CVE-2026-33300: Discourse: Hidden group names and access metadata are exposed to moderators through the `category-chatables` endpoint

• Severity: medium (CVSS 6.5 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: 2026-03-31 · updated 2026-07-24
• Weakness: CWE-200

Description

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authorization bypass in the Category Chatables Controller show action allowed moderators to get information on hidden groups names and user count. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Affected products

• discourse: from 2026.1.0 before 2026.1.3; from 2026.2.0 before 2026.2.2; 2026.3.0 — fixed in 2026.1.3, 2026.2.2

How to fix

Upgrade to a fixed version: discourse 2026.1.3, 2026.2.2. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/07f66658cce81a099a0d7115db5f3c69f5d3cca2
• https://github.com/discourse/discourse/security/advisories/GHSA-wrwm-vqx2-6x4v

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