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CVE-2021-34705
MEDIUM · CVSS 5.3
EPSS exploitation probability: 0%
Published 2021-09-23T03:15:17.240 · Last modified 2026-06-17T03:56:23.370

Summary

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.

Affected products

cisco — ios

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.