#VU122115 Stored cross-site scripting in Discourse - CVE-2025-66488
Published: January 29, 2026
Vulnerability identifier: #VU122115
Vulnerability risk: Low
CVSSv4.0: 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-2025-66488
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Discourse
Discourse
Software vendor:
Civilized Discourse Construction Kit, Inc.
Civilized Discourse Construction Kit, Inc.
Description
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data within S3 for uploads. A remote user can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
Remediation
Install updates from vendor's website.