cvedb.io
CVE-2026-2229
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-03-12T21:16:25.573 · Last modified 2026-07-02T12:17:01.900

Summary

ImpactThe undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination. The vulnerability exists because: * The isValidClientWindowBits() function only validates that the value contains ASCII di

Affected products

nodejs — undici

Does this affect you?

Add your gear to cvedb and we'll alert you only when nodejs ships something exploited.

Check my exposure →

References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.