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

> A null pointer dereference in a Rust Git library can cause a crash when processing blame hunks from buffers.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 May 2026

## What is RUSTSEC-2026-0184?

RUSTSEC-2026-0184 is a vulnerability in git2, published on 13 May 2026. 

### Official description

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.

## Which versions are affected by RUSTSEC-2026-0184?

1 open source package ship an affected version, including git2.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `git2` | crates.io | From 0.0.0-0 | 0.21.0 |

## How do I fix RUSTSEC-2026-0184?

Upgrade git2 to 0.21.0 or later.

## Is RUSTSEC-2026-0184 being exploited?

There is no known exploitation of RUSTSEC-2026-0184 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0184 and fix it if it is affected.

What it is: RUSTSEC-2026-0184 is a vulnerability in git2, published on 13 May 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0184 in the wild and no public exploit code.

Affected packages and fixed versions:
- git2 (crates.io): affected from 0.0.0-0; fixed in 0.21.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/RUSTSEC-2026-0184/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0184/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0184

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0184/
Summaries are generated and may contain mistakes; the official description above is the record.