```toml
[advisory]
id = "RUSTSEC-2023-0003"
package = "libgit2-sys"
date = "2023-01-20"
url = "https://github.com/rust-lang/git2-rs/security/advisories/GHSA-m4ch-rfv5-x5g3"
categories = ["crypto-failure"]
keywords = ["ssh", "mitm", "git"]
aliases = ["CVE-2023-22742", "GHSA-m4ch-rfv5-x5g3", "GHSA-8643-3wh5-rmjq"]

[versions]
patched = [">= 0.13.5, < 0.14.0", ">= 0.14.2"]
```

# git2 does not verify SSH keys by default

The git2 and libgit2-sys crates are Rust wrappers around the
[libgit2]() C library. It was discovered that libgit2 1.5.0
and below did not verify SSH host keys when establishing an SSH connection,
exposing users of the library to Man-In-the-Middle attacks.

The libgit2 team assigned [CVE-2023-22742][libgit2-advisory] to this
vulnerability. The following versions of the libgit2-sys Rust crate have been
released:

* libgit2-sys 0.14.2, updating the underlying libgit2 C library to version 1.5.1.
* libgit2-sys 0.13.5, updating the underlying libgit2 C library to version 1.4.5.

A new git2 crate version has also been released, 0.16.1. This version only
bumps its libgit2-sys dependency to ensure no vulnerable libgit2-sys versions
are used, but contains no code changes: if you update the libgit2-sys version
there is no need to also update the git2 crate version.

[You can learn more about this vulnerability in libgit2's advisory][libgit2-advisory]

[libgit2]: https://libgit2.org/
[libgit2-advisory]: https://github.com/libgit2/libgit2/security/advisories/GHSA-8643-3wh5-rmjq