CVE-2022-20699

CVE-2022-20699 is a stack-based buffer overflow (CWE-121, caused by improper input-size validation per CWE-1284) in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers, one of a set of related flaws fixed in the same Cisco advisory. It can be triggered remotely without authentication by sending crafted requests to the router's network-facing services; the available public PoC demonstrates unauthenticated remote code execution against the RV340 via its SSL VPN interface. A successful attacker can execute arbitrary code or commands, elevate privileges, bypass authentication and authorization protections, install unsigned software, or crash the device (denial of service). Any organization running these small-business routers is affected, with the highest risk for devices whose web management or SSL VPN interface is reachable from the internet. The flaw is confirmed to be exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2022-03-03, EPSS estimates a 72.5% probability of exploitation within 30 days, and at least one public proof-of-concept is available.

What to do: Upgrade all RV160, RV260, RV340/340W and RV345/345P routers to the fixed firmware released in Cisco's advisory, applying updates per vendor instructions as required by the CISA KEV entry. Until patched, limit exposure by restricting web management and SSL VPN to trusted source addresses or disabling SSL VPN where it is not needed. Because active exploitation and a public unauthenticated RCE PoC exist, prioritize internet-facing devices and check them for signs of compromise.