CVE-2026-55536

Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)

CRITICAL 9.1EPSS 0.5%

PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server _handle_connection() checks Chrome extension origins with re.match() and the unanchored expression chrome-extension://[a-z0-9]{32}. Extra trailing characters pass before websocket.accept(), allowing start_session commands and unauthorized browser automation. This issue is fixed in version 4.6.58.

Affected: MervinPraison · PraisonAI
CVSS v3.1 GITHUB: 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS: 0.52% chance of exploitation in the next 30 days, 43rd percentile
Published: 2026-08-25
Updated: 2026-08-28

Proof-of-concept exploits (1)

advisories/GHSA-6g6r-q6gw-w8fg

References

CVE Record
NVD entry