CVE-2026-40289

PraisonAI Browser Server allows unauthenticated WebSocket clients to hijack connected extension sessions

Published Apr 14, 2026 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed
Description
PraisonAI is a multi-agent teams system. In versions below 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents, the browser bridge (praisonai browser start) is vulnerable to unauthenticated remote session hijacking due to missing authentication and a bypassable origin check on its /ws WebSocket endpoint. The server binds to 0.0.0.0 by default and only validates the Origin header when one is present, meaning any non-browser client that omits the header is accepted without restriction. An unauthenticated network attacker can connect, send a start_session message, and the server will route it to the first idle browser-extension WebSocket (effectively hijacking that session) and then broadcast all resulting automation actions and outputs back to the attacker. This enables unauthorized remote control of connected browser automation sessions, leakage of sensitive page context and automation results, and misuse of model-backed browser actions in any environment where the bridge is network-reachable. This issue has been fixed in versions 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-8x8f-54wf-vv92 PraisonAI Browser Server allows unauthenticated WebSocket clients to hijack connected extension sessions
History
Type Values Removed Values Added
First Time appeared Praison
Praison praisonai
Praison praisonaiagents
CPEs cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*
cpe:2.3:a:praison:praisonaiagents:*:*:*:*:*:python:*:*
Vendors & Products Praison
Praison praisonai
Praison praisonaiagents
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mervinpraison
Mervinpraison praisonai
Mervinpraison praisonaiagents
Vendors & Products Mervinpraison
Mervinpraison praisonai
Mervinpraison praisonaiagents
Type Values Removed Values Added
Description PraisonAI is a multi-agent teams system. In versions below 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents, the browser bridge (praisonai browser start) is vulnerable to unauthenticated remote session hijacking due to missing authentication and a bypassable origin check on its /ws WebSocket endpoint. The server binds to 0.0.0.0 by default and only validates the Origin header when one is present, meaning any non-browser client that omits the header is accepted without restriction. An unauthenticated network attacker can connect, send a start_session message, and the server will route it to the first idle browser-extension WebSocket (effectively hijacking that session) and then broadcast all resulting automation actions and outputs back to the attacker. This enables unauthorized remote control of connected browser automation sessions, leakage of sensitive page context and automation results, and misuse of model-backed browser actions in any environment where the bridge is network-reachable. This issue has been fixed in versions 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents.
Title PraisonAI Browser Server allows unauthenticated WebSocket clients to hijack connected extension sessions
Weaknesses CWE-306
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Apr 14, 2026, 8:18 PM
Reserved
Apr 10, 2026, 8:22 PM
Status
Analyzed
Published
Apr 14, 2026, 4:17 AM
Modified
Oct 26, 2026, 10:10 PM