What’s Vulnerable › Vulnerabilities

CVE-2026-42583: Netty: Lz4FrameDecoder resource exhaustion

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-13 · updated 2026-10-26
• Weakness: CWE-400

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.

Affected products

• netty: before 4.1.133; from 4.2.0 before 4.2.13 — fixed in 4.1.133, 4.2.13

How to fix

Upgrade to a fixed version: netty 4.1.133, 4.2.13. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2026-42583 or the next vulnerability affects your stack