What’s Vulnerable › Vulnerabilities

CVE-2026-27935: Discourse leaks private topic metadata to non-authorized users

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-19 · updated 2026-06-17
• Weakness: CWE-201

Description

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a vulnerability in an API endpoint that discloses private topic metadata of admin users to moderator users even if the moderators do not have access to the private topics. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Affected products

• discourse: from 2026.1.0 before 2026.1.2; from 2026.2.0 before 2026.2.1; 2026.3.0 — fixed in 2026.1.2, 2026.2.1

How to fix

Upgrade to a fixed version: discourse 2026.1.2, 2026.2.1. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/c0f6e9a903800de0dda65c114418ae703d8a51fc
• https://github.com/discourse/discourse/commit/d8dbb4cb189cded8c9e8b3ada859fc0db3f41897
• https://github.com/discourse/discourse/commit/f37e4fdf8391e4a54f1885a3a5514d390eb28bab
• https://github.com/discourse/discourse/security/advisories/GHSA-wxqr-r4wv-cw76

Get alerted when CVE-2026-27935 or the next vulnerability affects your stack