CVE-2021-33478: Cisco IP Phone 8800 Firmware

Medium severity, CVSS 6.8. EPSS: 0.3% chance of exploitation in the next 30 days.

The TrustZone implementation in certain Broadcom MediaxChange firmware could allow an unauthenticated, physically proximate attacker to achieve arbitrary code execution in the TrustZone Trusted Execution Environment (TEE) of an affected device. This, for example, affects certain Cisco IP Phone and Wireless IP Phone products before 2021-07-07. Exploitation is possible only when the attacker can disassemble the device in order to control the voltage/current for chip pins.

Affected products

• Cisco IP Phone 8800 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8800 Series With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8811 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8811 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8841 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8841 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8845 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8845 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8851 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8851 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8861 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8861 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco IP Phone 8865 Firmware: before 14.0\(1\) (fixed in 14.0\(1\))
• Cisco IP Phone 8865 With Multiplatform Firmware: before 11.3\(4\) (fixed in 11.3\(4\))
• Cisco Wireless IP Phone 8821 Firmware: before 11.0\(6\)sr1 (fixed in 11.0\(6\)sr1)

Published 2021-07-22. Last modified 2026-06-17.