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. 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.
Other sources
websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, 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 in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/websocket-driverto a version that resolves this vulnerability.Fixed in 0.7.5 - Upgrade
Upgrade
websocket-driverto a version that resolves this vulnerability.Fixed in 0.7.5
Event History
Frequently Asked Questions
What is the severity of CVE-2026-54466?
CVE-2026-54466 has a critical severity rating of 9.2.
How does CVE-2026-54466 impact WebSocket communications?
CVE-2026-54466 allows message corruption via abuse of protocol length headers, potentially impacting server-client communication.
What software is affected by CVE-2026-54466?
CVE-2026-54466 affects the npm package websocket-driver.
How can I mitigate CVE-2026-54466?
To mitigate CVE-2026-54466, update to a patched version of the websocket-driver package.
What is the nature of the vulnerability in CVE-2026-54466?
CVE-2026-54466 involves exploiting length header encoding in the WebSocket protocol to corrupt messages.