CVE-2026-42587 — Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS
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…
Published: 2026-05-13 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7