# RUSTSEC-2023-0020: const-cstr is Unmaintained

> Unmaintained Rust crate allows memory corruption and panics via unsound CStr handling, requiring migration to alternative libraries.

- **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:** 12 Mar 2023

## What is RUSTSEC-2023-0020?

RUSTSEC-2023-0020 is a memory corruption vulnerability in const-cstr, published on 12 Mar 2023. 

### Official description

Last release was about five years ago.

The maintainer(s) have been unreachable to respond to any issues that may or may not include security issues.

The repository is now archived and there is no security policy in place to contact the maintainer(s) otherwise.

No direct fork exist.

# const-cstr is Unsound

The crate violates the safety contract of [ffi::CStr::from_bytes_with_nul_unchecked](https://doc.rust-lang.org/std/ffi/struct.CStr.html#method.from_bytes_with_nul_unchecked) used in `ConstCStr::as_cstr`

No interior nul bytes checking is done either by the constructor or the canonical macro to create the `ConstCStr`

# const-cstr Panic

Additionally the crate may cause runtime panics if statically compiled and ran with any untrusted data that is not nul-terminated.

This is however unlikely but the the crate should not be used for untrusted data in context where panic may create a DoS vector.

## Possible Alternatives

The below may or may not provide alternative(s)

- [const_str::cstr!](https://docs.rs/const-str/latest/const_str/macro.cstr.html)
- [cstr::cstr!](https://crates.io/crates/cstr)

## Which versions are affected by RUSTSEC-2023-0020?

1 open source package ship an affected version, including const-cstr.


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

## How do I fix RUSTSEC-2023-0020?

No fix has been published for RUSTSEC-2023-0020 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2023-0020 being exploited?

There is no known exploitation of RUSTSEC-2023-0020 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2023-0020 and fix it if it is affected.

What it is: RUSTSEC-2023-0020 is a memory corruption vulnerability in const-cstr, published on 12 Mar 2023. 
Exploitation: There is no known exploitation of RUSTSEC-2023-0020 in the wild and no public exploit code.

Affected packages and fixed versions:
- const-cstr (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-2023-0020/ (Markdown: https://insights.sbomify.com/RUSTSEC-2023-0020/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2023-0020

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2023-0020/
Summaries are generated and may contain mistakes; the official description above is the record.