CVE-2026-72724

MEDIUM 4.3

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

CVSS Score

4.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-639
Vendor	discourse
Product	discourse
Published	Aug 10, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Affected Versions

discourse / discourse

< 2026.1.6 >= 2026.5.0-latest, < 2026.5.2 >= 2026.6.0-latest, < 2026.6.1 >= 2026.7.0-latest, < 2026.7.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗