CVE-2021-34705 MEDIUM

CVE-2021-34705: Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability

Vendor Cisco
Product Cisco IOS
Weakness CWE-232
Published September 23, 2021
Last update September 16, 2024

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity Low

CVSS vector

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

What the vulnerability does

01Description

A vulnerability in the Voice Telephony Service Provider (VTSP) service of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured destination patterns and dial arbitrary numbers. This vulnerability is due to insufficient validation of dial strings at Foreign Exchange Office (FXO) interfaces. An attacker could exploit this vulnerability by sending a malformed dial string to an affected device via either the ISDN protocol or SIP. A successful exploit could allow the attacker to conduct toll fraud, resulting in unexpected financial impact to affected customers.

Key dates

02Disclosure timeline

September 23, 2021 CVE published
September 16, 2024 Record updated