CVE-2026-45416 is a high-severity allocation of resources without limits or throttling vulnerability in io.netty:netty-handler (maven), affecting versions >= 4.2.0.Final, <= 4.2.14.Final. It is fixed in 4.2.15.Final, 4.1.135.Final.
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.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
CVE-2026-45416 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (4.2.15.Final, 4.1.135.Final). Upgrading removes the vulnerable code path.
maven
io.netty:netty-handler (>= 4.2.0.Final, <= 4.2.14.Final)io.netty:netty-handler (<= 4.1.134.Final)io.netty:netty-handler → 4.2.15.Final (maven)io.netty:netty-handler → 4.1.135.Final (maven)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-45416 is reachable in your applications. Explore open-source security for your team.
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Upgrade the following packages to resolve this vulnerability:
io.netty:netty-handler to 4.2.15.Final or laterio.netty:netty-handler to 4.1.135.Final or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-45416 is a high-severity allocation of resources without limits or throttling vulnerability in io.netty:netty-handler (maven), affecting versions >= 4.2.0.Final, <= 4.2.14.Final. It is fixed in 4.2.15.Final, 4.1.135.Final. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
CVE-2026-45416 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
io.netty:netty-handler (maven) versions >= 4.2.0.Final, <= 4.2.14.Final is affected.
Yes. CVE-2026-45416 is fixed in 4.2.15.Final, 4.1.135.Final. Upgrade to this version or later.
Whether CVE-2026-45416 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
io.netty:netty-handler to 4.2.15.Final or laterio.netty:netty-handler to 4.1.135.Final or later