CVE-2026-61666

The websocket-driver library prior to 0.7.5, when used with the permessage-deflate extension, checks the message size limit against compressed data, not after decompression. This allows accepting messages larger than the configured maximum.

The websocket-driver library before version 0.7.5 incorrectly handles the frame length in the WebSocket protocol. By sending an indefinite sequence of bytes with the high bit set, an attacker can cause the server to parse these bytes as an ever-growing integer, leading to precision loss and incorrect payload parsing.

websocket-driver before version 0.8.1 is vulnerable to an attack where sending an HTTP request with an endless list of headers causes unbounded memory consumption in the receiving process.

The WebSocket library used with the permessage-deflate extension can accept messages larger than the configured maximum size. The limit is checked against the message frames' length headers, which give the size of compressed data, not the size after decompression.

In the websocket-driver library before version 0.8.1, the length header in the WebSocket protocol allows encoding an arbitrarily large integer as bytes with the high bit set. A server or client can send an indefinite sequence of 0x80 or higher bytes that are parsed into an ever-growing Ruby integer.