libuv is a multi-platform support library with a focus on asynchronous I/O. The `uv_getaddrinfo` function in `src/unix/getaddrinfo.c` (and its windows counterpart `src/win/getaddrinfo.c`), truncates hostnames to 256 characters before calling `getaddrinfo`. This behavior can be exploited to create addresses like `0x00007f000001`, which are considered valid by `getaddrinfo` and could allow an attacker to craft payloads that resolve to unintended IP addresses, bypassing developer checks. The vulnerability arises due to how the `hostname_ascii` variable (with a length of 256 bytes) is handled in `uv_getaddrinfo` and subsequently in `uv__idna_toas
The implementation of realpath in libuv < 10.22.1, < 12.18.4, and < 14.9.0 used within Node.js incorrectly determined the buffer size which can result in a buffer overflow if the resolved path is longer than 256 bytes.