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Vulnerability record · CVE-2021-33478 · published 22 July 2021

CVE-2021-33478: Cisco ip phone 8800 firmware memory buffer overflow vulnerability

Cisco · Ip Phone 8800 Firmware

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.

6.8 CVSS 3.1 Medium EPSS 0.30% · top 79.2% CWE-119 · Memory buffer overflow
6.8CVSS 3.1 base score, v2 4.6
0.30%EPSS exploitation probability, 30 days
NoNot in CISA KEV
15Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

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.

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

Affected products

15 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-brcm-mxc-jul2021-26LqUZUh Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-brcm-mxc-jul2021-26LqUZUh Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-33478), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.