# CVE-2023-34462: netty: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high perfor...

CVE-2023-34462 is fixed in 2 products on 1 platform, first by libnetty-java 1:4.1.48-9, released June 22, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-34462
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0246
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 22, 2023

## Description

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. The `SniHandler` can allocate up to 16MB of heap for each channel during the TLS handshake. When the handler or the channel does not have an idle timeout, it can be used to make a TCP server using the `SniHandler` to allocate 16MB of heap. The `SniHandler` class is a handler that waits for the TLS handshake to configure a `SslHandler` according to the indicated server name by the `ClientHello` record. For this matter it allocates a `ByteBuf` using the value defined in the `ClientHello` record. Normally the value of the packet should be smaller than the handshake packet but there are not checks done here and the way the code is written, it is possible to craft a packet that makes the `SslClientHelloHandler`. This vulnerability has been fixed in version 4.1.94.Final.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libnetty-java Ubuntu 22.04.1 LTS (jammy) | 1:4.1.48-4+deb11u2build0.22.04.1 | [libnetty-java 1:4.1.48-4+deb11u2build0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libnetty-java-1-4.1.48-4-deb11u2build0.22.04.1.md) | Oct 9, 2023 |
| Linux | libnetty-java Ubuntu 24.04.5 LTS (noble) | 1:4.1.48-9 | [libnetty-java 1:4.1.48-9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libnetty-java-1-4.1.48-9.md) | Jun 22, 2023 |
| Linux | netty Debian 11.6 (bullseye) | 1:4.1.48-4+deb11u2 | [DSA-5558-1](https://patchblox.com/security/data/fix/linux/dsa-5558-1.md) | Nov 18, 2023 |
| Linux | netty Debian 12.15 (bookworm) | 1:4.1.48-7+deb12u1 | [DSA-5558-1](https://patchblox.com/security/data/fix/linux/dsa-5558-1.md) | Nov 18, 2023 |
| Linux | netty Debian 13.5 (trixie) | 1:4.1.48-8 | [DEBIAN-CVE-2023-34462](https://patchblox.com/security/data/fix/linux/debian-cve-2023-34462.md) | Jun 22, 2023 |
| Linux | netty Debian 14 | 1:4.1.48-8 | [DEBIAN-CVE-2023-34462](https://patchblox.com/security/data/fix/linux/debian-cve-2023-34462.md) | Jun 22, 2023 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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