# RUSTSEC-2026-0338: Remote peer can panic quinn-proto with zero-length STREAM frames during unordered reads

> Remote attackers can crash applications using quinn-proto by sending zero-length STREAM frames during unordered reads, requiring an upgrade to fix.

- **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:** 14 Sep 2026
- **Also known as:** GHSA-465w-v9q3-7j98

## What is RUSTSEC-2026-0338?

RUSTSEC-2026-0338 is a denial of service vulnerability in quinn-proto, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When a stream is read in unordered mode (for example through `RecvStream::read(false)` in
quinn-proto or `read_unordered` in `quinn`), quinn-proto proactively deduplicates received data
by recording received ranges in a `RangeSet` through its `replace` method. When an incoming
STREAM frame carried an empty payload, the `Drop` implementation of the iterator returned by
`replace` inserted an empty range into the set, violating the invariant that stored ranges are
non-empty. Subsequent frames overlapping that region then caused a panic while processing the
stream.

A remote peer can trigger this with five small STREAM frames (two of them zero-length) once the
application has put the stream in unordered-read mode. The default ordered read path is not
affected.

The flaw was corrected in 0.11.18 by ignoring empty ranges in `RangeSet::replace`.

Thanks to Otto Hermann ([@ojhermann](https://github.com/ojhermann)) for reporting this issue.

## Which versions are affected by RUSTSEC-2026-0338?

1 open source package ship an affected version, including quinn-proto.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `quinn-proto` | crates.io | From 0.7.0 | 0.11.18 |

## How do I fix RUSTSEC-2026-0338?

Upgrade quinn-proto to 0.11.18 or later.

## Is RUSTSEC-2026-0338 being exploited?

There is no known exploitation of RUSTSEC-2026-0338 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0338 and fix it if it is affected.

What it is: RUSTSEC-2026-0338 is a denial of service vulnerability in quinn-proto, published on 14 Sep 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-2026-0338 in the wild and no public exploit code.

Affected packages and fixed versions:
- quinn-proto (crates.io): affected from 0.7.0; fixed in 0.11.18

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-2026-0338/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0338/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0338

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0338/
Summaries are generated and may contain mistakes; the official description above is the record.