CVE-2021-33478: Buffer Overflow

Published Jul 22, 2021
·
Updated

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 Software

15 affected components
Cisco Ip Phone 8800 Firmware<14.0\(1\)
Cisco Ip Phone 8800 Series With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8811 Firmware<14.0\(1\)
Cisco Ip Phone 8811 With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8841 Firmware<14.0\(1\)
Cisco Ip Phone 8841 With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8845 Firmware<14.0\(1\)
Cisco Ip Phone 8845 With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8851 Firmware<14.0\(1\)
Cisco Ip Phone 8851 With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8861 Firmware<14.0\(1\)
Cisco Ip Phone 8861 With Multiplatform Firmware<11.3\(4\)
Cisco Ip Phone 8865 Firmware<14.0\(1\)
Cisco Ip Phone 8865 With Multiplatform Firmware<11.3\(4\)
Cisco Wireless Ip Phone 8821 Firmware<11.0\(6\)sr1

Event History

Jul 22, 2021
CVE Published
via MITRE·04:53 PM
Data Sourced
via MITRE·04:53 PM
Description
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is CVE-2021-33478?

CVE-2021-33478 is a vulnerability that allows an unauthenticated, physically proximate attacker to achieve arbitrary code execution in the TrustZone Trusted Execution Environment (TEE) of certain Broadcom MediaxChange firmware.

2

Which devices are affected by CVE-2021-33478?

Cisco IP Phones and Cisco Wireless IP Phones are affected by CVE-2021-33478.

3

How does CVE-2021-33478 work?

CVE-2021-33478 leverages a flaw in the TrustZone implementation in certain Broadcom MediaxChange firmware, allowing an attacker to execute arbitrary code in the TEE of the affected device.

4

What is the severity of CVE-2021-33478?

The severity of CVE-2021-33478 is medium, with a CVSS score of 6.8.

5

Where can I find more information about CVE-2021-33478?

You can find more information about CVE-2021-33478 in the Cisco Security Advisory: [link](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-brcm-mxc-jul2021-26LqUZUh).

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203