CVE-2021-34705

MediumCVSS 5.3/10Last modified Jun 17, 2026

Description

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.

Metrics

CVSS 3.1 5.3/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Weakness enumeration

CWE-232

Affected software

No affected versions have been published.

Timeline

Published
Sep 23, 2021
Last modified
Jun 17, 2026
NVD status
Analyzed

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CVE-2021-34705: Medium severity, CVSS 5.3 | Vulnix