Information disclosure in Discourse - CVE-2026-47263
Published: July 1, 2026
Vulnerability identifier: #VU136590
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-47263
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Civilized Discourse Construction Kit, Inc.
Affected software:
Discourse
Discourse
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper access control in the MessageBus.publish call for /web_hook_events/ in Jobs::RedeliverWebHookEvents when processing webhook redeliveries. A remote attacker can subscribe to the channel and enumerate sequential webhook IDs to disclose sensitive information.
On instances where login_required is disabled, anonymous users can access the channel. The exposed payload may include request and response headers and bodies, private post content, user PII, and data returned by third-party endpoints.
How to mitigate CVE-2026-47263
Install security update from vendor's website.