# RUSTSEC-2020-0169: multi_mut is Unmaintained

> The unmaintained multi_mut crate has an unresolved soundness issue causing undefined behavior, requiring developers to migrate away from it.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Feb 2020

## What is RUSTSEC-2020-0169?

RUSTSEC-2020-0169 is a vulnerability in multi_mut, published on 7 Feb 2020. 

### Official description

Last release was about 6 years ago.

There is an outstanding [soundness issue](https://github.com/golddranks/multi_mut/issues/1).

The maintainer has not responded for two years to the existing soundness issue.

Rust compiler has enabled errors relating to LLVM noalias rules and may not
compile anymore where as the old compiler versions had turned these off.

The maintainer has stated:

> I will take no responsibility of undefined behaviour possibly caused by this crate.

This crate may or may not be suitable for use anymore given the outstanding issues.

## Which versions are affected by RUSTSEC-2020-0169?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `multi_mut` | crates.io | From 0.0.0-0 | None |

## How do I fix RUSTSEC-2020-0169?

No fix has been published for RUSTSEC-2020-0169 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2020-0169 being exploited?

There is no known exploitation of RUSTSEC-2020-0169 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2020-0169 and fix it if it is affected.

What it is: RUSTSEC-2020-0169 is a vulnerability in multi_mut, published on 7 Feb 2020. 
Exploitation: There is no known exploitation of RUSTSEC-2020-0169 in the wild and no public exploit code.

Affected packages and fixed versions:
- multi_mut (crates.io): affected from 0.0.0-0; no fix listed

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-2020-0169/ (Markdown: https://insights.sbomify.com/RUSTSEC-2020-0169/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2020-0169

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2020-0169/
Summaries are generated and may contain mistakes; the official description above is the record.