If this library is used in tandem with the permessage-deflate extension, a
WebSocket server or client can be made to accept messages that are larger than
the configured maximum message size. This is because this limit is checked
against the message frames' length headers, which give the size of the
compressed data, not the size after decompression. This can lead to applications
accepting larger messages than expected and exceeding their intended resource
usage.
The issue has been patched in version 0.8.1, by checking the length of messages after they are processed by incoming extensions. All users should upgrade to this version.
No known workarounds exist.
This issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.
Exploitability
AV:NAC:LAT:PPR:NUI:NVulnerable System
VC:NVI:NVA:LSubsequent System
SC:NSI:NSA:L6.3/CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:LResource Management