CVE-2026-43974

A flaw was found in gun. A malicious HTTP server can exploit this vulnerability by sending an unsolicited '101 Switching Protocols' response to a gun client. This action forces the client into a raw protocol mode, allowing the server to flood the client with arbitrary data. This uncontrolled data...

CVE-2026-43974

Unexpected Status Code or Return Value vulnerability in ninenines gun gunhttp module allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response. In gunhttp:handleinform/8, when a 101 Switching Protocols response is received over...

CVE-2026-43974

The CVE concerns the gun_http module of the Erlang-based Gun library (gun_http) in the Gun HTTP client. Affected versions: Gun 2.0.0 up to but not including 2.4.0. Root cause: when a 101 Switching Protocols response arrives over HTTP/1.1, Gun only validates the Upgrade header syntax and the strea...

EEF-CVE-2026-43974 gun HTTP/1.1 client accepts unsolicited 101 Switching Protocols response allowing server-driven protocol hijack and OOM

Summary Unexpected Status Code or Return Value vulnerability in ninenines gun gunhttp module allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response. In gunhttp:handleinform/8, when a 101 Switching Protocols response is receive...