CVE-2026-54463: websocket-driver: Memory exhaustion via abuse of protocol length headers

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-17 · updated 2026-10-24
Weakness: CWE-770

Description

websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, draft versions of the WebSocket protocol in websocket-driver include a length header that allows an arbitrarily large integer to be encoded as bytes with the high bit set, and a server or client can send an indefinite sequence of 0x80 or higher bytes that the peer parses into an ever-growing Ruby integer. This can make a WebSocket connection consume an unbounded amount of memory and lead to the host process running out of memory. This issue is fixed in version 0.8.1.

Affected products

faye websocket-driver-ruby: before 0.8.1 — fixed in 0.8.1
Rubygems Websocket-Driver: before 0.8.1; 0.1.0, 0.2.0, 0.2.1, 0.2.2, 0.2.3, 0.3.0 (+26) — fixed in 0.8.1

How to fix

Upgrade to a fixed version: faye websocket-driver-ruby 0.8.1; Rubygems Websocket-Driver 0.8.1. Check the vendor advisory for mitigations.

References

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