Description
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, `HttpContentEncoder` (the superclass of the production handler `HttpContentCompressor`) maintains a per-channel `ArrayDeque<CharSequence>` named `acceptEncodingQueue` that accumulates attacker-controlled data without any size limit. The queue is filled on the I/O thread for every inbound HTTP request and drained only when the application later writes a non-1xx response. This creates a resource exhaustion vulnerability when an attacker exploits HTTP/1.1 pipelining to flood the connection with requests faster than the application produces responses. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Published: 2026-07-29
Score: 6.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-q4f6-jm68-57ww Netty: [HttpContentEncoder] Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service
History

Wed, 29 Jul 2026 18:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in the Netty netty-codec-http component. A remote attacker can send HTTP requests containing highly compressed data. The HTTP decoder in netty-codec-http fails to properly limit the decompression of this content, causing the system to consume excessive memory. This can lead to memory exhaustion and a denial of service (DoS), making the service unavailable to legitimate users. Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, `HttpContentEncoder` (the superclass of the production handler `HttpContentCompressor`) maintains a per-channel `ArrayDeque<CharSequence>` named `acceptEncodingQueue` that accumulates attacker-controlled data without any size limit. The queue is filled on the I/O thread for every inbound HTTP request and drained only when the application later writes a non-1xx response. This creates a resource exhaustion vulnerability when an attacker exploits HTTP/1.1 pipelining to flood the connection with requests faster than the application produces responses. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Title io.netty/netty-codec-http: Netty: Memory exhaustion in netty-codec-http (decompression bomb) Netty HttpContentEncoder: Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service
Weaknesses CWE-770
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Tue, 28 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in the Netty netty-codec-http component. A remote attacker can send HTTP requests containing highly compressed data. The HTTP decoder in netty-codec-http fails to properly limit the decompression of this content, causing the system to consume excessive memory. This can lead to memory exhaustion and a denial of service (DoS), making the service unavailable to legitimate users.
Title io.netty/netty-codec-http: Netty: Memory exhaustion in netty-codec-http (decompression bomb)
Weaknesses CWE-409
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-29T18:00:37.588Z

Reserved: 2026-07-07T16:40:07.984Z

Link: CVE-2026-59899

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-09T00:00:00Z

Links: CVE-2026-59899 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-409

    Improper Handling of Highly Compressed Data (Data Amplification)

  • CWE-770

    Allocation of Resources Without Limits or Throttling