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CVE-2026-45416
Published:June 09, 2026
Updated:June 09, 2026
SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates "ctx.alloc().buffer(handshakeLength)" (line 161). The guard at line 140 is "handshakeLength > maxClientHelloLength && maxClientHelloLength != 0", and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes.
Affected Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.0.Final <netty-4.2.15.Final
Fix Suggestion:
Update to version netty-4.2.15.Final
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.0.0.Alpha1 <netty-4.1.135.Final
Fix Suggestion:
Update to version netty-4.1.135.Final
io.netty:netty-handler (JAVA):
Affected version(s) >=4.0.0.Alpha1 <4.1.135.Final
Fix Suggestion:
Update to version 4.1.135.Final
io.netty:netty-handler (JAVA):
Affected version(s) >=4.2.0.Final <4.2.15.Final
Fix Suggestion:
Update to version 4.2.15.Final
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CVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Allocation of Resources Without Limits or Throttling