CVE-2026-42583

Netty: Lz4FrameDecoder resource exhaustion

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.

Affected

netty · io.netty · netty-codec · netty-codec-compression

CVSS v3.1 GITHUB

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

EPSS

0.49% chance of exploitation in the next 30 days, 41st percentile

Published

2026-05-13

Updated

2026-05-14

Proof-of-concept exploits (1)

• advisories/GHSA-mj4r-2hfc-f8p6

Security advisories

• netty/netty/security/advisories/GHSA-mj4r-2hfc-f8p6

References

• CVE Record
• NVD entry