Vulnerability · Published Jun 22, 2023 · Assigned by GitHub_M
CVE-2023-34462netty-handler SniHandler 16MB allocation
Medium 6.5
In plain English
A medium-severity uncontrolled resource consumption in netty from netty. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.5% (higher than 85% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | netty | 1:4.1.48-7+deb12u1 | DSA-5558-1 |
| Debian:12 | netty | 1:4.1.48-7+deb12u1 | DEBIAN-CVE-2023-34462 |
| Debian:13 | netty | 1:4.1.48-8 | DEBIAN-CVE-2023-34462 |
| Debian:14 | netty | 1:4.1.48-8 | DEBIAN-CVE-2023-34462 |
| Maven | io.netty:netty-handler | 4.1.94.Final | GHSA-6mjq-h674-j845 |
| Ubuntu:22.04:LTS | netty | 1:4.1.48-4+deb11u2build0.22.04.1 | USN-6994-1 |
| Ubuntu:22.04:LTS | netty | 1:4.1.48-4+deb11u2build0.22.04.1 | UBUNTU-CVE-2023-34462 |
| Ubuntu:24.04:LTS | netty | 1:4.1.48-9 | UBUNTU-CVE-2023-34462 |
| Ubuntu:25.10 | netty | no fix listed | UBUNTU-CVE-2023-34462 |
| Ubuntu:26.10 | netty | no fix listed | UBUNTU-CVE-2023-34462 |
Affected products (as reported)
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/netty/netty/security/advisories/GHSA-6mjq-h674-j845 x_refsource_CONFIRM
- https://github.com/netty/netty/commit/535da17e45201ae4278c0479e6162bb4127d4c32 x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20230803-0001/
- https://www.debian.org/security/2023/dsa-5558
- https://security.netapp.com/advisory/ntap-20240621-0007/