CVE-2020-7662: Websocket-Extensions Project Websocket-Extensions

High severity, CVSS 7.5. EPSS: 3% chance of exploitation in the next 30 days.

websocket-extensions npm module prior to 0.1.4 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with the Sec-WebSocket-Extensions header.

Affected products

• Websocket-Extensions Project Websocket-Extensions: before 0.1.4 (fixed in 0.1.4)

Published 2020-06-02. Last modified 2026-06-17.