Cisco Small Business Routers Remote Command Execution & Denial of Service Vulnerability [CVE-2021-34730]

CVE number – CVE-2021-34730

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.

At the time of publication Cisco has not released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

Affected Products

  • Vulnerable ProductsThis vulnerability affects the following Cisco Small Business RV Series Routers if they have UPnP configured:
    • RV110W Wireless-N VPN Firewalls
    • RV130 VPN Routers
    • RV130W Wireless-N Multifunction VPN Routers
    • RV215W Wireless-N VPN RoutersNote: The UPnP service is enabled by default on LAN interfaces and disabled by default on WAN interfaces. If UPnP is disabled on both the LAN and WAN interfaces, the device is not considered vulnerable.

Determine the UPnP Configuration

To determine whether the UPnP feature is enabled on the LAN interface of a device, open the web-based management interface and navigate to Basic Settings > UPnP. If the Disable check box is unchecked, UPnP is enabled on the device.


Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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