CVE-2026-55833 PUBLISHED

Netty SPDY zlib header block continues decoded expansion after maxHeaderSize truncation

Assigner: GitHub_M
Reserved: 17.06.2026 Published: 20.07.2026 Updated: 21.07.2026

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded maxHeaderSize and marked the frame truncated in SpdyFrameCodec, allowing a remote peer to send a small compressed HEADERS block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Product Status

Vendor netty
Product netty
Versions
  • Version >= 4.2.0.Final, < 4.2.16.Final is affected
  • Version >= 4.1.0.Final, < 4.1.136.Final is affected

References

Problem Types

  • CWE-400: Uncontrolled Resource Consumption CWE