# RUSTSEC-2026-0266: `internment` 0.8.7 was removed from crates.io due to a malicious dependency

> A malicious dependency in the internment crate allowed arbitrary code execution during build, requiring users to upgrade to a safe version.

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

## What is RUSTSEC-2026-0266?

RUSTSEC-2026-0266 is a vulnerability in internment, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A new version of the `internment` crate was published with a direct dependency
on `proc-macro1`, which would execute a malicious build script.

The compromised version of this crate was published on 2026-08-20, and was
removed approximately 90 minutes later.

The compromised version was used as part of a malware campaign targeted at
users of `arrayref`, which was downloaded 2,285 times before being removed; see
[the `arrayref` advisory][arrayref-advisory] for more detail.

[arrayref-advisory]: https://rustsec.org/advisories/RUSTSEC-2026-0260.html

## Which versions are affected by RUSTSEC-2026-0266?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `internment` | crates.io | From 0.8.7-0 | None |

## How do I fix RUSTSEC-2026-0266?

No fix has been published for RUSTSEC-2026-0266 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2026-0266 being exploited?

There is no known exploitation of RUSTSEC-2026-0266 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0266 and fix it if it is affected.

What it is: RUSTSEC-2026-0266 is a vulnerability in internment, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of RUSTSEC-2026-0266 in the wild and no public exploit code.

Affected packages and fixed versions:
- internment (crates.io): affected from 0.8.7-0; 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-2026-0266/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0266/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0266

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0266/
Summaries are generated and may contain mistakes; the official description above is the record.