CVE-2015-4226: Cisco Unified IP Phones 9900 Series Firmware

High severity, CVSS 7.1. EPSS: 2.8% chance of exploitation in the next 30 days.

The packet-storing feature on Cisco 9900 phones with firmware 9.3(2) does not properly support the RTP protocol, which allows remote attackers to cause a denial of service (device hang) by sending malformed RTP packets after a call is answered, aka Bug ID CSCur39976.

Affected products

• Cisco Unified IP Phones 9900 Series Firmware: version 9.3(2) only

Published 2015-06-30. Last modified 2026-06-17.