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CVE-2026-40911

CRITICALCVSS 10/10EPSS 0.65%

Last modified

CVE-2026-40911 is a critical-severity vulnerability rated 10/10 on the CVSS scale. 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. EPSS estimates a 0.65% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
10/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
0.65%

46.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
WwbnAvideo<= 29.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-40911?
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.
How severe is CVE-2026-40911?
CVE-2026-40911 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 0.65% probability of exploitation in the next 30 days.
How do I fix CVE-2026-40911?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40911?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST