# RUSTSEC-2026-0293: Double free / use-after-free in `Consumer::skip` and `Consumer::clear` when an element's `Drop` panics

> A double free or use-after-free vulnerability in the Rust ring buffer library allows attackers to cause crashes or potentially execute code if element drop panics.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Sep 2026

## What is RUSTSEC-2026-0293?

RUSTSEC-2026-0293 is an use after free vulnerability in ringbuf, published on 21 Sep 2026. 

### Official description

`Consumer::skip()` and `Consumer::clear()` are not panic-safe. They drop the
consumed elements in place and only afterwards call `advance_read_index()` to move
the ring buffer's read index past them. If an element's `Drop` panics mid-loop,
`advance_read_index()` is never reached, so the read index still points at the
already-dropped elements. When the ring buffer is later dropped, its destructor
re-visits those slots and drops the same elements a second time — a double free
(CWE-415) / use-after-free (CWE-416) reachable from safe Rust, confirmed under
AddressSanitizer.

`Consumer::clear()` delegates to `Consumer::skip(self.len())`, so both share the
same root cause and the same fix.

## Mitigation

Update to 0.5.2 or later (fixed in agerasev/ringbuf#60).

## Which versions are affected by RUSTSEC-2026-0293?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ringbuf` | crates.io | From 0.0.0-0 | 0.5.2 |

## How do I fix RUSTSEC-2026-0293?

Upgrade ringbuf to 0.5.2 or later.

## Is RUSTSEC-2026-0293 being exploited?

There is no known exploitation of RUSTSEC-2026-0293 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0293 and fix it if it is affected.

What it is: RUSTSEC-2026-0293 is an use after free vulnerability in ringbuf, published on 21 Sep 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0293 in the wild and no public exploit code.

Affected packages and fixed versions:
- ringbuf (crates.io): affected from 0.0.0-0; fixed in 0.5.2

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-2026-0293/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0293/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0293

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0293/
Summaries are generated and may contain mistakes; the official description above is the record.