# RUSTSEC-2026-0127: Integer overflow in `array::ReadWrite::new()` leading to potential memory corruption

> An integer overflow in a Rust library's array constructor can cause memory corruption, potentially leading to code execution or crashes.

- **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:** 2 May 2026

## What is RUSTSEC-2026-0127?

RUSTSEC-2026-0127 is a vulnerability in accessor, published on 2 May 2026. 

### Official description

In `array::ReadWrite::new()` (line 83 of `accessor/src/array.rs`),
`let bytes = mem::size_of::<T>() * len` can overflow `usize` when `len` is
very large. In release mode, this silently wraps, potentially making
`bytes = 0`. The mapper then maps with 0 bytes, and subsequent accesses
(e.g. `read_volatile_at`) lead to undefined behavior or memory corruption.

Note: `array::ReadWrite::new()` itself is `unsafe`, so direct triggering
requires an `unsafe` block. However, the integer overflow violates the
implicit safety contract expected by callers and can lead to memory
corruption downstream.

## Which versions are affected by RUSTSEC-2026-0127?

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


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

## How do I fix RUSTSEC-2026-0127?

No fix has been published for RUSTSEC-2026-0127 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2026-0127 being exploited?

There is no known exploitation of RUSTSEC-2026-0127 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0127 and fix it if it is affected.

What it is: RUSTSEC-2026-0127 is a vulnerability in accessor, published on 2 May 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0127 in the wild and no public exploit code.

Affected packages and fixed versions:
- accessor (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-2026-0127/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0127/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0127

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0127/
Summaries are generated and may contain mistakes; the official description above is the record.