Regular Expression Denial of Service in websocket-extensions (NPM package)
High severity
GitHub Reviewed
Published
Jun 2, 2020
in
faye/websocket-extensions-node
•
Updated Jan 9, 2023
Description
Reviewed
Jun 3, 2020
Published to the GitHub Advisory Database
Jun 5, 2020
Last updated
Jan 9, 2023
Impact
The ReDoS flaw allows an attacker to exhaust the server's capacity to process
incoming requests by sending a WebSocket handshake request containing a header
of the following form:
That is, a header containing an unclosed string parameter value whose content is
a repeating two-byte sequence of a backslash and some other character. The
parser takes exponential time to reject this header as invalid, and this will
block the processing of any other work on the same thread. Thus if you are
running a single-threaded server, such a request can render your service
completely unavailable.
Patches
Users should upgrade to version 0.1.4.
Workarounds
There are no known work-arounds other than disabling any public-facing
WebSocket functionality you are operating.
References
References