CVE-2026-59898Medium▾ SunlitNetty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation
▾ Sunlit zone — Low / medium · no exploitation signal
impact 27.5 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 30.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.3%
An attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending Sec-WebSocket-Version: 7 and omitting Connection: Upgrade / Upgrade: websocket headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks.
io.netty:netty-codec-http >= 4.2.0.Final, <= 4.2.15.Finalio.netty:netty-codec-http < 4.1.136.FinalUpgrade to a patched release:
io.netty:netty-codec-http 4.2.16.Finalio.netty:netty-codec-http 4.1.136.FinalConnected by shared product, vendor, weakness, or advisory.
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