RUSTSEC-2026-0183: Potential undefined behavior when calling Remote::list()

What to do

1. See which version you have: cargo tree -i git2 (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p git2. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example git2 = "0.21.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

When calling Remote::list() for a remote of a git repository, when that remote does not advertise any references, git2 passes a null pointer to the unsafe function slice::from_raw_parts(). Based on the safety section documentation of function, data must be non-null even for slices of length zero. Thus, the use of a null pointer leads to undefined behavior.

References

• Package: crates.io/crates/git2
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0183.html
• Web: github.com/rust-lang/git2-rs/pull/1250

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for git2

• UnsoundRUSTSEC-2026-0008 · 2026-02-02Potential undefined behavior when dereferencing Buf struct
• UnsoundRUSTSEC-2026-0184 · 2026-05-13Potential undefined behavior with Signature from a buffer-created BlameHunk

Full security history of git2