# RUSTSEC-2026-0233: Crafted archives can cause a use-after-free during deserialization

> A crafted archive can trigger a use-after-free during deserialization, potentially allowing code execution or denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 May 2026

## What is RUSTSEC-2026-0233?

RUSTSEC-2026-0233 is an use after free vulnerability in rkyv, published on 11 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Insufficient archive range validation could allow a crafted archive to reach
`ArchivedString::deserialize` with an invalid pointer. A reported reproducer
used `rkyv::from_bytes` to deserialize a struct containing strings, a vector,
a box, and an optional hash map. AddressSanitizer detected a heap use-after-free
during string deserialization.

The flaw could be triggered through the safe checked deserialization API when
processing malicious archive bytes. Version 0.8.17 rejects the malformed
archive during validation. Users who process untrusted archives should upgrade
to 0.8.17 or later.

## Which versions are affected by RUSTSEC-2026-0233?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `rkyv` | crates.io | From 0.8.0-rc.1 | 0.8.17 |

## How do I fix RUSTSEC-2026-0233?

Upgrade rkyv to 0.8.17 or later.

## Is RUSTSEC-2026-0233 being exploited?

There is no known exploitation of RUSTSEC-2026-0233 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0233 and fix it if it is affected.

What it is: RUSTSEC-2026-0233 is an use after free vulnerability in rkyv, published on 11 May 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-2026-0233 in the wild and no public exploit code.

Affected packages and fixed versions:
- rkyv (crates.io): affected from 0.8.0-rc.1; fixed in 0.8.17

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-2026-0233/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0233/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0233

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0233/
Summaries are generated and may contain mistakes; the official description above is the record.