CVE-2026-42587

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

PUBLISHED Reserved 2026-04-28 | Published 2026-05-13 | Updated 2026-05-13 | Assigner GitHub_M

Problem types

CWE-400: Uncontrolled Resource Consumption

Product status

References

github.com/.../netty/security/advisories/GHSA-f6hv-jmp6-3vwv exploit

github.com/.../netty/security/advisories/GHSA-f6hv-jmp6-3vwv

cve.org (CVE-2026-42587)

nvd.nist.gov (CVE-2026-42587)

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