Cross-site scripting in AVideo - CVE-2026-40911
Published: November 11, 2026
Vulnerability identifier: #VU165901
CSH Severity: High
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]
CVE-ID: CVE-2026-40911
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary JavaScript in every connected user's browser context, including administrators, enabling account takeover and privileged actions.
The vulnerability exists due to unchecked evaluation of attacker-controlled message and callback fields in AVideo's YPTSocket plugin when relaying WebSocket broadcasts to client-side eval() sinks. A remote attacker can obtain an anonymous token and broadcast crafted JSON containing msg.autoEvalCodeOnHTML or callback fields to execute JavaScript across connected users when the plugin is enabled.
Affected software
AVideo
How to mitigate CVE-2026-40911
Install security update from vendor's website.
AVideo - update to 29.1.0