CVE-2021-33478: The TrustZone implementation in certain Broadcom MediaxChange firmware could allow an unauthenticated, physically proximate attacker to achi
Noroxi assessment
Priority: Monitor (action score 27/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.30% (FIRST EPSS).
- Physical access to the device is required. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to the record, no fixed version is available yet.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Update when a fix is released; follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Jul 22, 2021
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 23th percentile
- CWE
- CWE-119
Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 27 / 40 · 6.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| cisco | ip phone 8800 firmware | cpe:2.3:o:cisco:ip_phone_8800_firmware |
| cisco | ip phone 8800 series with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8800_series_with_multiplatform_firmware |
| cisco | ip phone 8811 firmware | cpe:2.3:o:cisco:ip_phone_8811_firmware |
| cisco | ip phone 8811 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8811_with_multiplatform_firmware |
| cisco | ip phone 8841 firmware | cpe:2.3:o:cisco:ip_phone_8841_firmware |
| cisco | ip phone 8841 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8841_with_multiplatform_firmware |
| cisco | ip phone 8845 firmware | cpe:2.3:o:cisco:ip_phone_8845_firmware |
| cisco | ip phone 8845 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8845_with_multiplatform_firmware |
| cisco | ip phone 8851 firmware | cpe:2.3:o:cisco:ip_phone_8851_firmware |
| cisco | ip phone 8851 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8851_with_multiplatform_firmware |
| cisco | ip phone 8861 firmware | cpe:2.3:o:cisco:ip_phone_8861_firmware |
| cisco | ip phone 8861 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_8861_with_multiplatform_firmware |
and 3 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco ip phone 8800 firmwarebefore 14.0\(1\)
- cisco ip phone 8800 series with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8811 firmwarebefore 14.0\(1\)
- cisco ip phone 8811 with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8841 firmwarebefore 14.0\(1\)
- cisco ip phone 8841 with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8845 firmwarebefore 14.0\(1\)
- cisco ip phone 8845 with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8851 firmwarebefore 14.0\(1\)
- cisco ip phone 8851 with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8861 firmwarebefore 14.0\(1\)
- cisco ip phone 8861 with multiplatform firmwarebefore 11.3\(4\)
- cisco ip phone 8865 firmwarebefore 14.0\(1\)
- cisco ip phone 8865 with multiplatform firmwarebefore 11.3\(4\)
- cisco wireless ip phone 8821 firmwarebefore 11.0\(6\)sr1
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-0325A vulnerability in the Session Initiation Protocol (SIP) call-handling functionality of Cisco IP Phone 7800 Series phones and Cisco IP Phone31Monitor
- CVE-2019-1766Cisco IP Phone 8800 Series File Upload Denial of Service Vulnerability30Monitor
- CVE-2019-1684Cisco IP Phone 7800 and 8800 Series Cisco Discovery Protocol and Link Layer Discovery Protocol Denial of Service Vulnerability26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0558 · Jul 8, 2021(Cisco Güvenlik Bildirimi)
Technical details
Attack conditions
- Physical access to the device is required.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Physical
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.