Cross-site scripting in Discourse - CVE-2026-53963
Published: July 1, 2026
Vulnerability identifier: #VU136602
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-53963
CWE-ID: CWE-79
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 user to escalate privileges.
The vulnerability exists due to cross-site scripting in the 2FA delete confirmation modal when rendering a malicious 2FA name. A remote user can use a malicious name for a 2FA on an attacker-controlled account to escalate privileges.
User interaction is required when an administrator impersonates the attacker-controlled account.
How to mitigate CVE-2026-53963
Install security update from vendor's website.