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Xav Ax8500 Firmware EUVDEUVD-2025-18881

| CVE-2025-5476 HIGH
Improper Isolation or Compartmentalization (CWE-653)
2025-06-21 zdi-disclosures@trendmicro.com
8.8
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Component isolation
Impact

This vulnerability presents high real-world risk across multiple dimensions: (1) CVSS 8.8 with attack vector Adjacent Network (AV:A) indicates moderate physical proximity requirement but no privileges, credentials, or user interaction needed (PR:N/UI:N); (2) Access vector is practical in parking lots, garages, and Bluetooth-proximate environments; (3) Complete confidentiality, integrity, and availability impact (C:H/I:H/A:H) means attackers gain unrestricted device control including vehicle infotainment, potentially affecting climate control, navigation, and phone connectivity; (4) The lack of L2CAP isolation is a fundamental protocol-level flaw unlikely to be accidentally mitigated, increasing likelihood of exploitation; (5) As a ZDI disclosure (ZDI-CAN-26284), this vulnerability has undergone formal analysis and likely has proof-of-concept capability; (6) In-vehicle systems present high-value targets for theft, stalking, and vehicle tampering. EPSS would likely be elevated given the adjacency-only requirement and no-interaction nature.

Exploit ScenarioDerived

An attacker with a laptop and Bluetooth adapter parks near a target vehicle containing an XAV-AX8500 system. Without any interaction from the vehicle owner, the attacker sends specially crafted L2CAP frames that exploit the channel isolation flaw to bypass authentication. Once authenticated, the attacker can read stored phone contacts and call history, modify navigation settings to redirect the driver, access stored WiFi credentials, or deny service by resetting the device—all while the owner remains unaware. A more targeted scenario involves an attacker preemptively establishing an unauthorized connection to a vehicle in a parking lot, then using stored credentials to lock the owner out of their own device during normal use, or inject malicious commands. The attack requires only Bluetooth proximity (typically 10-100 meters depending on antenna and environment) and a standard Bluetooth-capable computer, making it accessible to moderately skilled attackers.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 15, 2026

CVE-2025-5476 is an authentication bypass vulnerability in Sony XAV-AX8500 Bluetooth car audio systems caused by improper L2CAP channel isolation in ACL-U links. A network-adjacent attacker can completely bypass authentication without user interaction to gain full control (read, modify, execute) of the device. This is a critical vulnerability affecting in-vehicle infotainment systems with potential safety and privacy implications.

RemediationAI

Immediate remediation requires: (1) Contact Sony directly or monitor their security advisory page for XAV-AX8500 firmware patches that address L2CAP channel isolation; (2) Apply firmware update to the device when available (typically done via USB or wireless update mechanism); (3) Until patches are available, mitigate by disabling Bluetooth on the device when parked in public areas, or reducing Bluetooth transmission power if supported; (4) Keep the device physically secure and avoid parking in high-risk areas; (5) Monitor for unauthorized pairing attempts in the device's Bluetooth settings; (6) If vehicle connectivity is critical, consider disabling sensitive functions (navigation history, stored credentials) from syncing to the infotainment system. Vendor patch status should be confirmed at Sony's official support page for the XAV-AX8500.

Affected VersionsENISA

XAV-AX8500 2.00.01

Affected Packages

euvd xav_ax8500 no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The vulnerability exists in the Bluetooth implementation of the Sony XAV-AX8500, specifically in the handling of ACL-U (Asynchronous Connection-Less Unauthenticated) links at the L2CAP (Logical Link Control and Adaptation Protocol) layer. The root cause is CWE-653 (Improper Isolation or Compartmentalization), where L2CAP channels are not properly isolated, allowing an attacker on an adjacent Bluetooth network to establish unauthorized channels and bypass the device's authentication mechanisms. This is fundamentally a protocol implementation flaw where the device fails to enforce proper state management and channel segregation in its Bluetooth stack, particularly in the early stages of connection establishment before authentication occurs.

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Severity by source

NVD PRIMARY 8.8 HIGH
AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch released
Mar 15, 2026 - 21:35 nvd
Patch available
CVE Published
Jun 21, 2025 - 01:15 nvd
HIGH 8.8

DescriptionCVE.org

Sony XAV-AX8500 Bluetooth Improper Isolation Authentication Bypass Vulnerability. This vulnerability allows network-adjacent attackers to bypass authentication on affected Sony XAV-AX8500 devices. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the implementation of ACL-U links. The issue results from the lack of L2CAP channel isolation. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-26284.

Executive ViewAI

Why It Matters

Sony XAV-AX8500 in-vehicle infotainment systems contain a Bluetooth authentication bypass vulnerability that allows attackers within wireless range to gain unauthorized access without credentials. Organizations operating vehicle fleets or managing connected car deployments should assess exposure immediately, as this vulnerability could enable unauthorized control of vehicle systems and data access.

Business Impact: High
Compensating Controls

Apply vendor patch. If immediate patching is not possible: disable Bluetooth functionality on affected devices where operationally acceptable, restrict physical proximity to vehicles through secure parking facilities, or isolate affected devices on segregated network segments with restricted access controls.

Threat Intelligence Overview

EPSS Score
0.0%
Top 94% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
High

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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