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 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