CVE-2021-33478

Name: CVE-2021-33478
Creator: NVD / NIST
Published: 2021-07-22T17:15:09.51+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.8/10EPSS 0.30%

Last modified Jun 17, 2026

CVE-2021-33478 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. 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. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.30%

22.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
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

References

Timeline

Published: Jul 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33478?

How severe is CVE-2021-33478?

CVE-2021-33478 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33478?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33478?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST