# RUSTSEC-2026-0056: `tokio-codec` is unmaintained

> The tokio-codec crate is unmaintained, requiring users to migrate to tokio-util to avoid potential future security risks.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not stated
- **Attackable:** Not stated
- **Victim action needed:** Not stated
- **Fix available:** No
- **Published:** 20 Mar 2026

## What is RUSTSEC-2026-0056?

RUSTSEC-2026-0056 is a vulnerability in tokio-codec, published on 20 Mar 2026. 

### Official description

The [`tokio-codec`](https://crates.io/crates/tokio-codec) crate is unmaintained.
It was part of the Tokio 0.1 ecosystem and has been superseded by the [`tokio-util`](https://crates.io/crates/tokio-util) crate.

## Which versions are affected by RUSTSEC-2026-0056?

1 open source package ship an affected version, including tokio-codec.


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

## How do I fix RUSTSEC-2026-0056?

No fix has been published for RUSTSEC-2026-0056 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2026-0056 being exploited?

There is no known exploitation of RUSTSEC-2026-0056 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0056 and fix it if it is affected.

What it is: RUSTSEC-2026-0056 is a vulnerability in tokio-codec, published on 20 Mar 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0056 in the wild and no public exploit code.

Affected packages and fixed versions:
- tokio-codec (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-2026-0056/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0056/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0056

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0056/
Summaries are generated and may contain mistakes; the official description above is the record.