CVE-2021-1520

6.7 MEDIUM 0.3% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine with an admin-level account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-05-06 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:31 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 6.7 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-05-06 13:15 UTC
Last modified: 2026-06-17 03:31 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-123
Record status: Modified

Affected

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

Attack profile CVSS 3.1 · 6.7

Attack vector: Local
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-1520.md and follow it. Check whether this project is affected by CVE-2021-1520. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

· More options · Status badge

Download Square Reddit

Fix and advisories

References

NVD record · CVE.org record