CVE-2026-54466: websocket-driver: Message corruption via abuse of protocol length headers
Impact The frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer.
Published Jul 15, 2026
Affected packages
websocket-driver
- Ecosystem
- npm
- Affected
- < 0.7.5
- Fixed in
- 0.7.5
- Check
npm ls websocket-driver
Advisory details
From the GitHub Advisory Database (CC BY 4.0).
Impact
The frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer. Since JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly.
Patches
The issue has been patched in version 0.7.5 by rejecting the message if the length header exceeds the configured maximum message length. All users should upgrade to this version.
Workarounds
No known workarounds exist.
Acknowledgements
This issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.
Credited to pranjalithakur.
References
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology