CVE-2026-89044
Published:September 10, 2026
Updated:September 22, 2026
Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks.
Affected Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.1.0.Final <netty-4.1.138.FinalFix Suggestion:
Update to version netty-4.1.138.Finalhttps://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.0.Final <netty-4.2.18.FinalFix Suggestion:
Update to version netty-4.2.18.Finalio.netty:netty-codec-http (JAVA):
Affected version(s) >=4.1.0.Final <4.1.138.FinalFix Suggestion:
Update to version 4.1.138.Finalio.netty:netty-codec-http (JAVA):
Affected version(s) >=4.2.0.Final <4.2.18.FinalFix Suggestion:
Update to version 4.2.18.FinalRelated Resources (9)
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Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
EPSS
Base Score:
0.24