CVE-2026-27153
Received Received - Intake
Improper Access Control in Discourse Allows Unauthorized DM Export

Publication date: 2026-02-26

Last updated on: 2026-03-02

Assigner: GitHub, Inc.

Description
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, moderators could export user Chat DMs via the CSV export endpoint by exploiting an overly permissive allowlist in `can_export_entity?`. The method allowed moderators to export any entity not explicitly blocked instead of restricting to an explicit allowlist. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
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Meta Information
Published
2026-02-26
Last Modified
2026-03-02
Generated
2026-06-16
AI Q&A
2026-02-27
EPSS Evaluated
2026-06-14
NVD
CVE-2026-27153
EUVD
EUVD-2026-8894
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
discourse discourse to 2025.12.2 (exc)
discourse discourse From 2026.1.0 (inc) to 2026.1.1 (exc)
discourse discourse 2026.2.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
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Executive Summary

This vulnerability exists in the Discourse open source discussion platform prior to versions 2025.12.2, 2026.1.1, and 2026.2.0. It involves an overly permissive allowlist in the method `can_export_entity?` used for exporting data. Specifically, moderators could exploit this flaw to export user Chat Direct Messages (DMs) via the CSV export endpoint. Instead of restricting exports to an explicit allowlist of entities, the method allowed exporting any entity that was not explicitly blocked.

Impact Analysis

The vulnerability allows moderators to export user private Chat DMs that they should not have access to. This could lead to unauthorized disclosure of private user communications, potentially compromising user privacy and trust in the platform.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, upgrade your Discourse installation to one of the patched versions: 2025.12.2, 2026.1.1, or 2026.2.0.

No known workarounds are available, so applying the update is the immediate and recommended step.

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