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Improper Handling of Length Parameter Inconsistency

CVE-2026-54466

Severity High
Score 9.2/10

Summary

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. This issue affects websocket-driver versions prior to 0.7.5.

  • LOW
  • NETWORK
  • NONE
  • NONE

CWE-130 - Improper Handling of Length Parameter Inconsistency

The software parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

References

Advisory Timeline

  • Published