CVE-2026-42583

Netty: Lz4FrameDecoder resource exhaustion

State: Published
Severity: 7.5 High
Published: May 13, 2026
Updated: May 14, 2026
Reserved: Apr 28, 2026

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Lz4FrameDecoder allocates a ByteBuf of size decompressedLength (up to 32 MB per block) before LZ4 runs. A peer only needs a 21-byte header plus compressedLength payload bytes - 22 bytes if compressedLength == 1 - to force that allocation. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Scores

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

Weaknesses

CWE-400 Uncontrolled Resource Consumption
CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

Product	Versions
nettynetty	>= 4.2.0.Alpha1, < 4.2.13.FinalAffected < 4.1.133.FinalAffected
netty-codecio.netty	< 4.1.133.FinalAffected
netty-codec-compressionio.netty	< 4.2.13.FinalAffected

References

https://github.com/netty/netty/security/advisories/GHSA-mj4r-2hfc-f8p6

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