RUSTSEC-2026-0008: Potential undefined behavior when dereferencing Buf struct

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 = "0.20.4") 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

if we dereference the Buf struct right after calling new() or default() on Buf struct, it passes Null Pointer to the unsafe function slice::from_raw_parts. Based on the safety section documentation of function, data must be non-null and aligned even for zero-length slices or slices of ZSTs. Thus, passing Null Pointer will lead to undefined behavior.

References

• Package: crates.io/crates/git2
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0008.html
• Web: github.com/rust-lang/git2-rs/pull/1213

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-2026-0183 · 2026-05-12Potential undefined behavior when calling Remote::list()
• UnsoundRUSTSEC-2026-0184 · 2026-05-13Potential undefined behavior with Signature from a buffer-created BlameHunk

Full security history of git2