daphne: WebSocket handshake header smuggling through autobahn splitlines() mishandling of non-standard line separators

daphne before 4.2.2 reconstructs a raw HTTP request from Twisted's parsed headers and feeds it to autobahn for WebSocket handshake processing. Twisted does not treat \x0b, \x0c, \x1c, \x1d, \x1e, or \x85 as header line separators, but autobahn decodes header values to str and calls splitlines. An...

CVE-2026-44546

The vulnerability (CVE-2026-44546) affects the Daphne web server prior to 4.2.2. It stems from a parser differential between Twisted and Autobahn: Twisted does not treat certain bytes (0x0b, 0x0c, 0x1c, 0x1d, 0x1e, 0x85) as header separators, while Autobahn decodes header values to str and calls ...