Netty: Prior to versions 4.1.136.Final and 4.2.16.Final, HttpContentEncoder (the superclass of the production handler HttpContentCompressor) maintains a… (CVE-2026-59899)
Netty versions prior to 4.1.136.Final and 4.2.16.Final contain a resource exhaustion vulnerability in the HttpContentEncoder class. This class maintains an unbounded queue that accumulates attacker-controlled data for each channel, which can be exploited via HTTP/1.1 pipelining to flood the connection with requests faster than responses are produced. The issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
AI Analysis
Technical Summary
Netty is an asynchronous, event-driven network application framework. In versions before 4.1.136.Final and 4.2.16.Final, the HttpContentEncoder class (superclass of HttpContentCompressor) maintains a per-channel ArrayDeque named acceptEncodingQueue that accumulates attacker-controlled data without any size limit. This queue is filled on the I/O thread for every inbound HTTP request and drained only when the application writes a non-1xx response. An attacker can exploit HTTP/1.1 pipelining to send requests faster than the application produces responses, causing resource exhaustion. This vulnerability is tracked as CVE-2026-59899 and has a CVSS 3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). The issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Potential Impact
The vulnerability allows an unauthenticated remote attacker to cause a denial of service via resource exhaustion by flooding the connection with HTTP requests faster than the application can respond. This leads to excessive memory consumption on the server side due to an unbounded queue accumulating attacker-controlled data, potentially impacting availability.
Mitigation Recommendations
Upgrade Netty to version 4.1.136.Final or later, or 4.2.16.Final or later, where this issue has been fixed. No other mitigations are indicated by the vendor advisory.
Netty: Prior to versions 4.1.136.Final and 4.2.16.Final, HttpContentEncoder (the superclass of the production handler HttpContentCompressor) maintains a… (CVE-2026-59899)
Description
Netty versions prior to 4.1.136.Final and 4.2.16.Final contain a resource exhaustion vulnerability in the HttpContentEncoder class. This class maintains an unbounded queue that accumulates attacker-controlled data for each channel, which can be exploited via HTTP/1.1 pipelining to flood the connection with requests faster than responses are produced. The issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Netty is an asynchronous, event-driven network application framework. In versions before 4.1.136.Final and 4.2.16.Final, the HttpContentEncoder class (superclass of HttpContentCompressor) maintains a per-channel ArrayDeque named acceptEncodingQueue that accumulates attacker-controlled data without any size limit. This queue is filled on the I/O thread for every inbound HTTP request and drained only when the application writes a non-1xx response. An attacker can exploit HTTP/1.1 pipelining to send requests faster than the application produces responses, causing resource exhaustion. This vulnerability is tracked as CVE-2026-59899 and has a CVSS 3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). The issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Potential Impact
The vulnerability allows an unauthenticated remote attacker to cause a denial of service via resource exhaustion by flooding the connection with HTTP requests faster than the application can respond. This leads to excessive memory consumption on the server side due to an unbounded queue accumulating attacker-controlled data, potentially impacting availability.
Mitigation Recommendations
Upgrade Netty to version 4.1.136.Final or later, or 4.2.16.Final or later, where this issue has been fixed. No other mitigations are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-q4f6-jm68-57ww
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-59899"]
- Ecosystems
- ["Maven"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 4.0
Threat ID: 6a6150d39c2644c7f8da06e4
Added to database: 07/22/2026, 23:22:59 UTC
Last enriched: 08/08/2026, 16:59:07 UTC
Last updated: 09/05/2026, 10:52:10 UTC
Views: 74
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