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Fencer Vulns
medium 6.8

CVE-2021-33478 json

The TrustZone implementation in certain Broadcom MediaxChange firmware could allow an unauthenticated, physically proximate attacker to ach…

published 2021-07-22 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20181

cvss
6.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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.

Patch / fix

  • 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

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.8 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.