Insufficient authentication in the MQTT backend (broker) allows an attacker to access and even manipulate the telemetry data of the entire fleet of vehicles using the HopeChart HQT-401 telematics unit. Other models are possibly affected too.
Multiple vulnerabilities were identified:
- The MQTT backend does not require authentication, allowing unauthorized connections from an attacker.
- The vehicles publish their telemetry data (e.g. GPS Location, speed, odometer, fuel, etc) as messages in public topics. The backend also sends commands to the vehicles as MQTT posts in public topics. As a result, an attacker can access the confidential data of the entire fleet that is managed by the backend.
- The MQTT messages sent by the vehicles or the backend are not encrypted or authenticated. An attacker can create and post messages to impersonate a vehicle or the backend. The attacker could then, for example, send incorrect information to the backend about the vehicle's location.
- The backend can inject data into a vehicle´s CAN bus by sending a specific MQTT message on a public topic. Because these messages are not authenticated or encrypted, an attacker could impersonate the backend, create a fake message and inject CAN data in any vehicle managed by the backend.
The confirmed version is 201808021036, however further versions have been also identified as potentially impacted.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-20). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines at low or medium mission impact and sooner than that at high, and watch for a fix.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it