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CVE-2026-93573
Published:September 18, 2026
Updated:October 09, 2026
A flaw was found in Netty's HTTP/1.1 decoder. This vulnerability allows a remote attacker to bypass "Transfer-Encoding" header validation by splitting the "Transfer-Encoding" field across multiple headers, with the last field containing a non-final transfer coding like "gzip" or "deflate". This bypass can lead to HTTP request smuggling, enabling attackers to bypass security controls, desynchronize request processing, or cause requests to be processed in an unintended context.
Affected Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.1.132.Final <netty-4.1.138.Final
Fix Suggestion:
Update to version netty-4.1.138.Final
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.12.Final <netty-4.2.18.Final
Fix Suggestion:
Update to version netty-4.2.18.Final
io.netty:netty-codec-http (JAVA):
Affected version(s) >=4.1.132.Final <4.1.138.Final
Fix Suggestion:
Update to version 4.1.138.Final
io.netty:netty-codec-http (JAVA):
Affected version(s) >=4.2.12.Final <4.2.18.Final
Fix Suggestion:
Update to version 4.2.18.Final
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CVSS 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:
0.90