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+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "git2"
+date = "2026-05-13"
+url = "https://github.com/rust-lang/git2-rs/pull/1254"
+informational = "unsound"
+keywords = ["git2"]
+
+[versions]
+patched = ["> 0.20.4"]
+```
+
+# Potential undefined behavior with Signature from a buffer-created BlameHunk
+
+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 `Signature`s based on null pointers; attempting to access the data of the `Signature`s leads to dereferencing null pointers.