CVE-2021-34705CWE-232

Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability

Medium · published September 23, 2021

CVSS v3.1
5.3
EPSS
1%
Percentile
62.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.01006 · 62.7th percentile
Weakness
CWE-232 · Improper Handling of Undefined Values
Published
2021-09-23T02:26Z
EPSS history
Timeline
  • 23 SEP 02:26Z
    Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability
    cvelistv5