CVE-2020-3516: Cisco IOS XE

Medium severity, CVSS 4.3. EPSS: 1.7% chance of exploitation in the next 30 days.

A vulnerability in the web server authentication of Cisco IOS XE Software could allow an authenticated, remote attacker to crash the web server on the device. The vulnerability is due to insufficient input validation during authentication. An attacker could exploit this vulnerability by entering unexpected characters during a valid authentication. A successful exploit could allow the attacker to crash the web server on the device, which must be manually recovered by disabling and re-enabling the web server.

Affected products

• Cisco IOS XE: before 16.9.6 (fixed in 16.9.6); from 16.12.0, before 16.12.2 (fixed in 16.12.2); from 17.1.0, before 17.1.1 (fixed in 17.1.1); version 17.2.1 only

Published 2020-09-24. Last modified 2026-06-17.