Sourced fromThe GitHub Security Advisory Database.

Regular Expression Denial of Service in websocket-extensions (NPM package)

Impact

The ReDoS flaw allows an attacker to exhaust the server's capacity to processincoming requests by sending a WebSocket handshake request containing a headerof the following form:

Sec-WebSocket-Extensions: a; b="\c\c\c\c\c\c\c\c\c\c ...

That is, a header containing an unclosed string parameter value whose content isa repeating two-byte sequence of a backslash and some other character. Theparser takes exponential time to reject this header as invalid, and this willblock the processing of any other work on the same thread. Thus if you arerunning a single-threaded server, such a request can render your servicecompletely unavailable.

Patches

Users should upgrade to version 0.1.4.

Workarounds

... (truncated)

Affected versions: < 0.1.4

Sourced fromwebsocket-extensions's changelog.

0.1.4 / 2020-06-02

• Remove a ReDoS vulnerability in the header parser (CVE-2020-7662, reported byRobert McLaughlin)
• Change license from MIT to Apache 2.0

• 8efd0cd Bump version to 0.1.4
• 3dad4ad Remove ReDoS vulnerability in the Sec-WebSocket-Extensions header parser
• 4a76c75 Add Node versions 13 and 14 on Travis
• 44a677a Formatting change: {...} should have spaces inside the braces
• f6c50ab Let npm reformat package.json
• 2d211f3 Change markdown formatting of docs.
• 0b62083 Update Travis target versions.
• 729a465 Switch license to Apache 2.0.
• See full diff incompare view

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