Io.netty:netty codec http: Netty: [HttpContentEncoder] Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service (CVE-2026-59899)
The vulnerability in io.netty:netty-codec-http involves the HttpContentEncoder class maintaining an unbounded per-connection queue that accumulates attacker-controlled data without size limits. This queue grows when HTTP/1.1 pipelining is exploited by sending requests faster than the application responds, leading to resource exhaustion and potential denial of service. No patch or official fix information is currently available.
AI Analysis
Technical Summary
The HttpContentEncoder class in io.netty:netty-codec-http maintains a per-channel ArrayDeque named acceptEncodingQueue that accumulates data from inbound HTTP requests without any size limitation. This queue is filled on the I/O thread for every inbound request and only drained when the application writes a non-1xx response. An attacker can exploit HTTP/1.1 pipelining to flood the connection with requests faster than responses are produced, causing unbounded queue growth and resource exhaustion, resulting in a denial of service condition.
Potential Impact
This vulnerability allows an attacker to cause resource exhaustion on the server by exploiting HTTP/1.1 pipelining to flood a connection with requests, leading to unbounded growth of the acceptEncodingQueue. This can degrade service availability or cause denial of service due to excessive memory consumption.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider limiting or disabling HTTP/1.1 pipelining if feasible, or applying application-level request rate limiting to mitigate resource exhaustion risks.
Io.netty:netty codec http: Netty: [HttpContentEncoder] Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service (CVE-2026-59899)
Description
The vulnerability in io.netty:netty-codec-http involves the HttpContentEncoder class maintaining an unbounded per-connection queue that accumulates attacker-controlled data without size limits. This queue grows when HTTP/1.1 pipelining is exploited by sending requests faster than the application responds, leading to resource exhaustion and potential denial of service. No patch or official fix information is currently available.
CVSS v4.0
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The HttpContentEncoder class in io.netty:netty-codec-http maintains a per-channel ArrayDeque named acceptEncodingQueue that accumulates data from inbound HTTP requests without any size limitation. This queue is filled on the I/O thread for every inbound request and only drained when the application writes a non-1xx response. An attacker can exploit HTTP/1.1 pipelining to flood the connection with requests faster than responses are produced, causing unbounded queue growth and resource exhaustion, resulting in a denial of service condition.
Potential Impact
This vulnerability allows an attacker to cause resource exhaustion on the server by exploiting HTTP/1.1 pipelining to flood a connection with requests, leading to unbounded growth of the acceptEncodingQueue. This can degrade service availability or cause denial of service due to excessive memory consumption.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider limiting or disabling HTTP/1.1 pipelining if feasible, or applying application-level request rate limiting to mitigate resource exhaustion risks.
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: 07/22/2026, 23:30:06 UTC
Last updated: 07/22/2026, 23:30:06 UTC
Views: 2
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