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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
2026-06-17
Advisory published
2026-06-12
Advisory updated
2026-06-17

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44786 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44786

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-44786 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44786

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.