Ip Phone 8800 FirmwareOperating system · Cisco
CVE-2021-33478
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA vulnerability in Broadcom's TrustZone implementation within MediaxChange firmware allows an unauthenticated attacker with physical access to achieve arbitrary code execution in the Trusted Execution Environment (TEE) by manipulating voltage/current on chip pins through device disassembly. This affects Cisco IP Phone and Wireless Phone products running affected firmware versions prior to the July 2021 patch.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Ip Phone 8800 FirmwareOperating system
< 14.0\(1\)
Ip Phone 8800 Series With Multiplatform FirmwareOperating system
< 11.3\(4\)
Ip Phone 8811 FirmwareOperating system
< 14.0\(1\)
Ip Phone 8811 With Multiplatform FirmwareOperating system
< 11.3\(4\)
Ip Phone 8841 FirmwareOperating system
< 14.0\(1\)
Ip Phone 8841 With Multiplatform FirmwareOperating system
< 11.3\(4\)
Ip Phone 8845 FirmwareOperating system
< 14.0\(1\)
Ip Phone 8845 With Multiplatform FirmwareOperating system
< 11.3\(4\)CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Cisco IP Phone 8800 series modelLocate the model number on the device physical label or check via the phone's admin interface under Device > Hardware Info. Confirm the model is one of: 8800, 8811, 8841, or 8845.Affected if Device model is Cisco IP Phone 8800, 8811, 8841, or 8845 and physical access to the device is possible.
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Determine firmware typeCheck the phone's admin interface or boot screen to identify whether the device runs standard firmware or Multiplatform Firmware (MPF).Affected if The device runs either standard Cisco firmware or Multiplatform Firmware.
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Check installed firmware versionAccess the phone's web interface or admin menu and navigate to Device Information or Status > Firmware Version. Record the exact version string.Affected if Firmware version is visible and can be compared to affected ranges.
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Compare version to affected rangesCompare your installed version: for standard firmware, check if it is earlier than 14.0(1); for Multiplatform Firmware, check if it is earlier than 11.3(4). Note that version formats may vary.Affected if Standard firmware version is below 14.0(1) OR Multiplatform Firmware version is below 11.3(4).
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Assess physical security of device locationEvaluate whether the device is located in an area where an attacker could physically access, disassemble, and manipulate the device without detection.Affected if Device is in a publicly accessible or unsecured location where physical tampering is feasible.
You are affected if you have a Cisco IP Phone 8800, 8811, 8841, or 8845 running firmware below 14.0(1) (standard) or below 11.3(4) (multiplatform) and the device is physically accessible to untrusted individuals.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data11.314.0
Apply the vendor-supplied firmware update released before 2021-07-07 for affected Cisco IP Phone and Wireless IP Phone products. Since exploitation requires physical device disassembly, ensure devices are in physically secure locations.
Fix this in Ip Phone 8800 Firmware
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33478 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-33478 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data