PatchSiren cyber security CVE debrief

CVE-2026-44786 discourse CVE debrief

CVE-2026-44786 is a HIGH severity vulnerability in Discourse, an open-source discussion platform. Chat events for public category channels were published to MessageBus without permission scoping. This allowed any MessageBus subscriber without chat enabled to receive chat message payloads in real time. The affected versions are from 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. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026.5.0-latest.1.

Vendor: discourse
Product: Unknown
CVSS: HIGH 7.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-12
Original CVE updated: 2026-06-12
Advisory published: 2026-06-12
Advisory updated: 2026-06-12

Who should care

Users of Discourse, especially those with public category channels, should be aware of this vulnerability. Administrators of Discourse instances should check their version and update to a patched version if necessary.

Technical summary

The vulnerability has a CVSS score of 7.5 and is classified as HIGH severity. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. The weakness is CWE-200, Information Exposure.

Defensive priority

HIGH

Recommended defensive actions

Update to a patched version of Discourse: 2026.1.4, 2026.3.1, 2026.4.1, or 2026.5.0-latest.1.
Review MessageBus subscribers and ensure they are properly configured.

Evidence notes

The CVE record [cve-org] and NVD detail [nvd] provide official information about the vulnerability. The source reference [ref-4] provides additional context from the Discourse security advisory.

Official resources

CVE-2026-44786 was published on 2026-06-12T21:16:22.313Z and has not been modified since then.