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CVE-2026-72724

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

Published: Aug 10, 2026Updated: Aug 11, 2026 Sources: CVE List NVDCWE-639
4.3MEDIUM
NVD MITRE
EPSS Score
0.5%
Top 62.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-639

Affected Products

discourse
commercial·USaka discourse.org
discourse
Web & CMS Plugins

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://github.com/discourse/discourse/commit/1276d7032af8803956c74ae87ccfd976938dcd75
github.com
https://github.com/discourse/discourse/commit/45ab6d54076de9ca4965888974d4416d5b48e83c
github.com
https://github.com/discourse/discourse/commit/49efe1d7f098f2ce7301908815a211cc9248270f
github.com
and 6 more references View all →

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