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Fencer Intel
high 8.8

CVE-2026-5768 json

Fourth Frontier Frontier X Mobile Application, Frontier X2 Missing Authentication for Critical Function

published 5mo ago modified 3mo ago also EUVD-2026-33368

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

The Frontier X2 device allows unauthenticated BLE read/write access to critical GATT characteristics without enforcing pairing authentication or authorization. This allows attackers within BLE range to perform unauthorized control of device functions, including starting/stopping activities, triggering vibrations, causing denial-of-service conditions, and fuzzing characteristic values to induce unexpected behavior. Additionally, the Frontier X mobile application lacks proper BLE device authentication, allowing attackers to impersonate a legitimate Frontier X2 device and connect to the application. By cloning BLE advertisements and exposing expected GATT characteristics, attackers can manipulate activity states and inject fabricated health telemetry such as breathing rate, heart rate, strain, and other health-related data into the mobile application.

Patch / fix

  • Fourth Frontier Frontier X Android application 15.0.0
  • Fourth Frontier Frontier X IOS application 25.0.0

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSMA-26-148-01 updated cvss 8.8

Fourth Frontier Frontier X Mobile Application, Frontier X2

  • Fourth Frontier Frontier X Android application <v15.0.0 Fourth Frontier Frontier X IOS application <v25.0.0 Fourth Frontier Frontier X2
    affected: mitigation “Fourth Frontier is aware of the vulnerability and is working on a fix. Users are encouraged to reach out to Fourth Frontier directly for assistance. https://fourthfrontier.com/pages/contact-usl.” fourthfrontier.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
5mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Fourth Frontier Frontier X Android application
  • Fourth Frontier Frontier X IOS application
  • Fourth Frontier Frontier X2

Classification

Weakness
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

Fencer Intel 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.