Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-42581— Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization

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之前版本和4.1.133.Final之前版本存在环境问题漏洞，该漏洞源于HttpObjectDecoder对HTTP/1.0请求中同时存在Transfer-Encoding和Content-Length标头时未移除冲突的Content-Length，可能导致请求夹带攻击。

CVSS 5.8 · Medium EPSS 0.68% · P51

Possible ATT&CK Techniques 1 AI

T1071.001 · Web Protocols

Affected Version Matrix 2

VendorProduct Version RangeStatus
netty netty >= 4.2.0.Alpha1, < 4.2.13.Final affected
< 4.1.133.Final affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-42581

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization
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, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. 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:C/C:N/I:L/A:N
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之前版本和4.1.133.Final之前版本存在环境问题漏洞，该漏洞源于HttpObjectDecoder对HTTP/1.0请求中同时存在Transfer-Encoding和Content-Length标头时未移除冲突的Content-Length，可能导致请求夹带攻击。
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 -

II. Public POCs for CVE-2026-42581

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-42581

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-42581 (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-2026-42584 7.3 HIGH Netty: HttpClientCodec response desynchronization
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-2026-44248 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

Same product: netty
Same vendor: netty
Same weakness: CWE-444

V. Comments for CVE-2026-42581

No comments yet

Leave a comment