# CVE-2021-34730: Memory corruption in Cisco Small Business RV Series Router Firmware

> Unauthenticated remote attackers can execute arbitrary code as root or cause denial of service on Cisco Small Business routers via crafted UPnP requests.

- **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:** 18 Aug 2021
- **Updated:** 7 Nov 2024
- **Also known as:** GHSA-9c26-qcv5-q5qj

## What is CVE-2021-34730?

CVE-2021-34730 is a critical memory corruption vulnerability in Cisco Application Extension Platform, published on 18 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Universal Plug-and-Play (UPnP) service of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an unauthenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of incoming UPnP traffic. An attacker could exploit this vulnerability by sending a crafted UPnP request to an affected device. A successful exploit could allow the attacker to execute arbitrary code as the root user on the underlying operating system or cause the device to reload, resulting in a DoS condition. Cisco has not released software updates that address this vulnerability.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2021-34730?

It affects 5 products.


Products: Cisco Application Extension Platform, Cisco Rv110w Wireless-N Vpn Firewall Firmware, Cisco Rv130 Vpn Router Firmware, Cisco Rv130w Wireless-N Multifunction Vpn Router Firmware, Cisco Rv215w Wireless-N Vpn Router Firmware.

## How do I fix CVE-2021-34730?

No fix has been published for CVE-2021-34730 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-34730 being exploited?

There is no known exploitation of CVE-2021-34730 in the wild and no public exploit code.

Public exploit code:

- Cisco RV110w UPnP stack overflow  (github_poc): https://github.com/badmonkey7/CVE-2021-34730

## Other vulnerabilities in Cisco Application Extension Platform

- [CVE-2021-1146](https://insights.sbomify.com/CVE-2021-1146/): Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Command Injection Vulnerabilities (high 7.2)
- [CVE-2021-1147](https://insights.sbomify.com/CVE-2021-1147/): Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Command Injection Vulnerabilities (high 7.2)
- [CVE-2021-1148](https://insights.sbomify.com/CVE-2021-1148/): Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Command Injection Vulnerabilities (high 7.2)
- [CVE-2021-1149](https://insights.sbomify.com/CVE-2021-1149/): Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Command Injection Vulnerabilities (high 7.2)
- [CVE-2021-1150](https://insights.sbomify.com/CVE-2021-1150/): Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers Management Interface Command Injection Vulnerabilities (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-34730 and fix it if it is affected.

What it is: CVE-2021-34730 is a critical memory corruption vulnerability in Cisco Application Extension Platform, published on 18 Aug 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-2021-34730 in the wild and no public exploit code.

Affected product: Cisco Application Extension Platform. 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-2021-34730/ (Markdown: https://insights.sbomify.com/CVE-2021-34730/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-34730
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-34730
- OSV: https://osv.dev/vulnerability/CVE-2021-34730

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-34730/
Summaries are generated and may contain mistakes; the official description above is the record.