CVE-2021-35951

Device bricking via unsigned Bluetooth firmware updates

Published Dec 26, 2022 · Updated Apr 14, 2025

Unauthenticated firmware updates in Fastrack Reflex 2.0 firmware 90.89 allow remote attackers to brick the tracker over Bluetooth LE. The Nordic DFU 0.1 OTA path performs no signature verification before accepting attacker-supplied firmware. Bluetooth LE range is the access gate, and a malicious image can render the physical tracker inoperable.

CVSS severity7.5
High
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Unauthenticated firmware updates in Fastrack Reflex 2.0 firmware 90.89 allow remote attackers to brick the tracker over Bluetooth LE. The Nordic DFU 0.1 OTA path performs no signature verification before accepting attacker-supplied firmware. Bluetooth LE range is the access gate, and a malicious image can render the physical tracker inoperable.

The record

CVE
CVE-2021-35951
Published
Dec 26, 2022
Updated
Apr 14, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1495
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1495Firmware Corruption

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo