Riskcovery

CVE-2026-42587

Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS

State
Published
Severity
7.5 High
Published
May 13, 2026
Updated
Sep 18, 2026
Reserved
Apr 28, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HGitHub_M
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hredhat-SADP

Weaknesses

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

Affected Products

ProductVersions
nettynetty
  • >= 4.2.0.Alpha1, < 4.2.13.FinalAffected
  • < 4.1.133.FinalAffected
netty-codec-httpio.netty
  • >= 4.2.0.Alpha1, < 4.2.13.FinalAffected
  • < 4.1.133.FinalAffected
netty-codec-http2io.netty
  • >= 4.2.0.Alpha1, < 4.2.13.FinalAffected
  • < 4.1.133.FinalAffected

References

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