CVE-2020-3161 CRITICAL

CVE-2020-3161: Cisco IP Phones Web Server Remote Code Execution and Denial of Service Vulnerability

Vendor Cisco
Product Cisco IP phone
Weakness CWE-20 · Input validation
KEV Status Known Exploited
Published April 15, 2020
Last update October 21, 2025

CVSS base score

9.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

A vulnerability in the web server for Cisco IP Phones could allow an unauthenticated, remote attacker to execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web server of a targeted device. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a DoS condition.

CISA mandated remediation

02CISA Required Action

Apply updates per vendor instructions.

Key dates

03Disclosure timeline

April 15, 2020 CVE published
October 21, 2025 Record updated