Missing Authentication for Critical Function in Discourse - CVE-2026-26078
Published: July 1, 2026
Vulnerability identifier: #VU136125
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-26078
CWE-ID: CWE-306
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 modify or delete Patreon pledge data and trigger patron-to-group synchronization.
The vulnerability exists due to improper authentication in the Patreon plugin webhook endpoint when handling webhook requests with a blank patreon_webhook_secret site setting. A remote attacker can send a specially crafted webhook payload with a forged signature to modify or delete Patreon pledge data and trigger patron-to-group synchronization.
Exploitation is possible only when the patreon_webhook_secret site setting is left empty.
How to mitigate CVE-2026-26078
Install security update from vendor's website.