CVE-2026-72724

Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch

Published Aug 10, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before checking whether the user can preview the selected chat channel. An authenticated user can pair a public channel ID with a private thread ID in a /onebox.json request and obtain private thread message content. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Discourse
Discourse discourse
Vendors & Products Discourse
Discourse discourse
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before checking whether the user can preview the selected chat channel. An authenticated user can pair a public channel ID with a private thread ID in a /onebox.json request and obtain private thread message content. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Title Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch
Weaknesses CWE-639
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 11, 2026, 1:57 AM
Reserved
Aug 10, 2026, 1:48 PM
Status
Deferred
Published
Aug 10, 2026, 4:19 PM
Modified
Sep 8, 2026, 8:54 PM