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CVE-2026-40911

WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks

Published: Apr 21, 2026Updated: Apr 21, 2026 Sources: CVE List NVD
10.0CVSS
CRITICAL

WWBN AVideo is an open source video platform. In versions 29.0 and prior, the YPTSocket plugin's WebSocket server relays attacker-supplied JSON message bodies to every connected client without sanitizing the `msg` or `callback` fields. On the client side, `plugin/YPTSocket/script.js` contains two `eval()` sinks fed directly by those relayed fields (`json.msg.autoEvalCodeOnHTML` at line 568 and `json.callback` at line 95). Because tokens are minted for anonymous visitors and never revalidated beyond decryption, an unauthenticated attacker can broadcast arbitrary JavaScript that executes in the origin of every currently-connected user (including administrators), resulting in universal account takeover, session theft, and privileged action execution. Commit c08694bf6264eb4decceb78c711baee2609b4efd contains a fix.

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High

Weaknesses

Affected Products

AVideo
WWBN

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

Timeline

Published
Apr 21, 2026
Last Updated
Apr 21, 2026

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