High 7.5Published May 13, 2026

CVE-2026-42587Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS

Updated under an hour ago (Oct 26, 2026, 1:10 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Sep 18, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

netty netty netty:netty (from the name)	from 4.2.0.Alpha1, < 4.2.13.Final; before 4.1.133.Final	CNA record
io.netty netty-codec-http io.netty:netty_codec_http (from the name)	from 4.2.0.Alpha1, < 4.2.13.Final; before 4.1.133.Final	CNA record
io.netty netty-codec-http2 io.netty:netty_codec_http2 (from the name)	from 4.2.0.Alpha1, < 4.2.13.Final; before 4.1.133.Final	CNA record
Red Hat Cryostat 4 on RHEL 9 redhat:cryostat	from 4.2.0-10 not affected	CISA ADP
Red Hat Red Hat AMQ Broker 7.13.6 redhat:amq_broker	from codec-http not affected	CISA ADP
Red Hat Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 redhat:apache_camel_spring_boot	from codec-http not affected; from codec-http2 not affected	CISA ADP
Red Hat Red Hat build of Quarkus 3.27.4 redhat:quarkus	from codec-http not affected; from codec-http2 not affected	CISA ADP
Red Hat Red Hat Data Grid 8.6.2 redhat:jboss_data_grid	from codec-http not affected; from codec-http2 not affected	CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7 redhat:jboss_enterprise_application_platform_els	from 0:2.16.0-22.redhat_00057.1.el7eap not affected	CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 redhat:jboss_enterprise_application_platform_xp	from codec-http2 not affected	CISA ADP
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References

References

https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv	x-refsource-confirm, exploit, mitigation, vendor-advisory
https://access.redhat.com/errata/RHSA-2026:23808
https://access.redhat.com/errata/RHSA-2026:24502
https://access.redhat.com/errata/RHSA-2026:25123
https://access.redhat.com/errata/RHSA-2026:28010
https://access.redhat.com/errata/RHSA-2026:34608
https://access.redhat.com/errata/RHSA-2026:36820
https://access.redhat.com/errata/RHSA-2026:37390
https://access.redhat.com/errata/RHSA-2026:41951
https://access.redhat.com/errata/RHSA-2026:42644
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.