CVE-2020-3408

HIGH

Cisco IOS and IOS XE - Unauthenticated Denial of Service via Split DNS Regex Timeout

Title source: llm
STIX 2.1

Description

A vulnerability in the Split DNS feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability occurs because the regular expression (regex) engine that is used with the Split DNS feature of affected releases may time out when it processes the DNS name list configuration. An attacker could exploit this vulnerability by trying to resolve an address or hostname that the affected device handles. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

References (1)

Core 1
Core References

Scores

CVSS v3 8.6
EPSS 0.0116
EPSS Percentile 78.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400 CWE-185
Status published
Products (2)
cisco/ios 15.8\(3\)m3
cisco/ios_xe 15.8\(3\)m3
Published Sep 24, 2020
Tracked Since Feb 18, 2026