CVE-2026-42584— Netty: HttpClientCodec response desynchronization
Quick assessment
Affected
netty netty
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Netty是Netty社区的一款非阻塞I/O客户端-服务器框架，它主要用于开发Java网络应用程序，如协议服务器和客户端等。 Netty 4.2.13.Final和4.1.133.Final之前版本存在环境问题漏洞，该漏洞源于HttpClientCodec在配对响应和请求时存在逻辑问题，可能导致解析错误。
Possible ATT&CK Techniques 3 AI
T1043 T1071 · Application Layer Protocol T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 4
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| io.netty | netty-codec-http | >= 4.2.0.Alpha1, < 4.2.13.Final |
affected |
< 4.1.133.Final |
affected | ||
| netty | netty | >= 4.2.0.Alpha1, < 4.2.13.Final |
affected |
< 4.1.133.Final |
affected |
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I. Basic Information for CVE-2026-42584
Vulnerability Information
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Vulnerability Title
Netty: HttpClientCodec response desynchronization
Source: CVE Program / CVE List V5
Vulnerability Description
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
HTTP请求的解释不一致性(HTTP请求私运)
Source: CVE Program / CVE List V5
Vulnerability Title
Netty 环境问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Netty是Netty社区的一款非阻塞I/O客户端-服务器框架，它主要用于开发Java网络应用程序，如协议服务器和客户端等。 Netty 4.2.13.Final和4.1.133.Final之前版本存在环境问题漏洞，该漏洞源于HttpClientCodec在配对响应和请求时存在逻辑问题，可能导致解析错误。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| netty | netty | >= 4.2.0.Alpha1, < 4.2.13.Final | - |
|
| io.netty | netty-codec-http | >= 4.2.0.Alpha1, < 4.2.13.Final | - |
|
II. Public POCs for CVE-2026-42584
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
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Vendor Advisories for CVE-2026-42584 (1)
Same Patch Batch · netty · 2026-05-13 · 12 CVEs total
| CVE-2026-42587 | 7.5 HIGH | Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy e |
| CVE-2026-42582 | 7.5 HIGH | Netty: HTTP/3 QPACK literal unbounded allocation |
| CVE-2026-42579 | 7.5 HIGH | Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder) |
| CVE-2026-42583 | 7.5 HIGH | Netty: Lz4FrameDecoder resource exhaustion |
| CVE-2026-42577 | 7.5 HIGH | Netty: epoll transport denial of service via RST on half-closed TCP connection |
| CVE-2026-42586 | 6.8 MEDIUM | Netty: CRLF Injection in Netty Redis Codec Encoder |
| CVE-2026-42580 | 6.5 MEDIUM | Netty: HTTP Request Smuggling due to incorrect chunk size parsing |
| CVE-2026-42585 | 6.5 MEDIUM | Netty: HTTP Request Smuggling due to malformed Transfer-Encoding |
| CVE-2026-42581 | 5.8 MEDIUM | Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization |
| CVE-2026-44248 | 5.3 MEDIUM | Netty: Resource exhaustion in MqttDecoder |
| CVE-2026-42578 | 2.9 LOW | Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation |
IV. Related Vulnerabilities
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CVE-2026-100666
Netty 4.2.0 through 4.2.16 Response Desynchronization via Ht -
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Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypas -
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CVE-2026-100663
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CVE-2026-100662
Netty HTTP/3 QPACK encoder-stream unbounded memory exhaustio
Same vendor: netty
-
CVE-2026-100666
Netty 4.2.0 through 4.2.16 Response Desynchronization via Ht -
CVE-2026-100665
Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypas -
CVE-2026-100663
Netty HTTP/1 CONNECT authority-form mistranslated to malform -
CVE-2026-100664
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CVE-2026-100662
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Same weakness: CWE-444
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CVE-2026-100724
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CVE-2026-100666
Netty 4.2.0 through 4.2.16 Response Desynchronization via Ht
V. Comments for CVE-2026-42584
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