CVE-2021-1520: Cisco RV340, RV340W, RV345, and RV345P Dual WAN Gigabit VPN Routers Local Privilege Escalation Vulnerability

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-05-06 · updated 2026-06-17
Weakness: CWE-123

Description

A vulnerability in the internal message processing of Cisco RV340, RV340W, RV345, and RV345P Dual WAN Gigabit VPN Routers could allow an authenticated, local attacker to run arbitrary commands with root privileges on the underlying operating system (OS). This vulnerability exists because an internal messaging service does not properly sanitize input. An attacker could exploit this vulnerability by first authenticating to the device and then sending a crafted request to the internal service. A successful exploit could allow the attacker to run arbitrary commands with root privileges on the underlying OS. To exploit this vulnerability, the attacker must have valid Administrator credentials for the device.

Affected products

Cisco Rv340 Firmware: before 1.0.03.21 — fixed in 1.0.03.21
Cisco Rv340W Firmware: before 1.0.03.21 — fixed in 1.0.03.21
Cisco Rv345 Firmware: before 1.0.03.21 — fixed in 1.0.03.21
Cisco Rv345P Firmware: before 1.0.03.21 — fixed in 1.0.03.21

How to fix

Upgrade to a fixed version: Cisco Rv340 Firmware 1.0.03.21; Cisco Rv340W Firmware 1.0.03.21; Cisco Rv345 Firmware 1.0.03.21; Cisco Rv345P Firmware 1.0.03.21. Check the vendor advisory for mitigations.

References

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