# CVE-2021-34345: Stack Based Overflow Vulnerability in NVR Storage Expansion

> A stack buffer overflow in QNAP NVR Storage Expansion allows attackers to execute arbitrary code on affected devices.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Sep 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-vhmr-2r99-xhqw

## What is CVE-2021-34345?

CVE-2021-34345 is a critical memory corruption vulnerability in QNAP Systems Inc. NVR Storage Expansion, published on 10 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A stack buffer overflow vulnerability has been reported to affect QNAP device running NVR Storage Expansion. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of NVR Storage Expansion: NVR Storage Expansion 1.0.6 ( 2021/08/03 ) and later

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-34345?

It affects 14 products.


Products: Qnap Ej1600 Firmware, Qnap Tl-D1600s Firmware, Qnap Tl-D400s Firmware, Qnap Tl-D800c Firmware, Qnap Tl-D800s Firmware, Qnap Tl-R1200c-Rp Firmware, Qnap Tl-R1200s-Rp Firmware, Qnap Tl-R1220sep-Rp Firmware, Qnap Tl-R1620sdc Firmware, Qnap Tl-R1620sep-Rp Firmware, Qnap Tl-R400s Firmware, Qnap Tr-002 Firmware, Qnap Tr-004 Firmware, Qnap Tr-004u Firmware.

## How do I fix CVE-2021-34345?

No fix has been published for CVE-2021-34345 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-34345 being exploited?

There is no known exploitation of CVE-2021-34345 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-34345 and fix it if it is affected.

What it is: CVE-2021-34345 is a critical memory corruption vulnerability in QNAP Systems Inc. NVR Storage Expansion, published on 10 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-34345 in the wild and no public exploit code.

Affected product: QNAP Systems Inc. NVR Storage Expansion. No package-level version data is available, so check the vendor advisory linked from the reference page.

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/CVE-2021-34345/ (Markdown: https://insights.sbomify.com/CVE-2021-34345/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-34345
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-34345
- OSV: https://osv.dev/vulnerability/CVE-2021-34345

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-34345/
Summaries are generated and may contain mistakes; the official description above is the record.