RUSTSEC-2026-0184: Potential undefined behavior with Signature from a buffer-created BlameHunk

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 a Blame is created via Blame::blame_buffer(), and a BlameHunk is retrieved, the pointers to the original author, original committer, final author, and final committer may be null if unavailable. The corresponding BlameHunk methods then create Signatures based on null pointers; attempting to access the data of the Signatures leads to dereferencing null pointers.

References

• Package: crates.io/crates/git2
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0184.html
• Web: github.com/rust-lang/git2-rs/pull/1254

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-2026-0183 · 2026-05-12Potential undefined behavior when calling Remote::list()

Full security history of git2