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.
Project Subscriptions
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-f6hv-jmp6-3vwv | Netty: HttpContentDecompressor maxAllocation bypass when Content-Encoding set to br/zstd/snappy leads to decompression bomb DoS |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Mon, 18 May 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* |
Thu, 14 May 2026 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Io.netty
Io.netty netty-codec-http Io.netty netty-codec-http2 Netty Netty netty |
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| Vendors & Products |
Io.netty
Io.netty netty-codec-http Io.netty netty-codec-http2 Netty Netty netty |
Wed, 13 May 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS | |
| Weaknesses | CWE-400 | |
| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-05-13T18:44:09.298Z
Reserved: 2026-04-28T17:26:12.086Z
Link: CVE-2026-42587
No data.
Status : Analyzed
Published: 2026-05-13T19:17:24.460
Modified: 2026-05-18T12:20:06.340
Link: CVE-2026-42587
No data.
OpenCVE Enrichment
Updated: 2026-05-14T14:33:59Z
Weaknesses
Github GHSA