CVE-2026-54466
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk18th percentile - higher than 18% of all known CVEs
Summary
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.
Risk Assessment
An attacker can remotely manipulate data transmitted over WebSocket, potentially leading to application malfunction or session hijacking.
Recommendation
Immediately update the websocket-driver library to version 0.7.5 or later.
Other vulnerabilities in websocket-driver
See all- CVE-2026-61666High
websocket-driver before version 0.8.2 has a vulnerability in WebSocket::Driver.server() that passes a malformed Host header to URI.parse in lib/websocket/http/request.rb without catching URI::InvalidURIError, allowing a remote client to crash a TCP-backed WebSocket server when the application does not catch the error from parse(). This issue is fixed in version 0.8.2.
- CVE-2026-54490Medium
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.
- CVE-2026-54465High
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.
- CVE-2026-54464Medium
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.
- CVE-2026-54463High
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.
Original NVD description (English source)
websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS