CVE-2026-18282

Executive Summary

CVE-2026-18282 is a heap-based buffer overflow vulnerability in the AVRCP (Audio/Video Remote Control Profile) packet handling routine of the Sony XAV-9500ES in-car entertainment system. A network-adjacent attacker who can pair a malicious Bluetooth device with the head unit can trigger remote code execution without any authentication requirements. The vulnerability carries a CVSS score of 8.0 and allows complete compromise of the device — including arbitrary code execution in the context of the target system. As of the time of this report, the vendor has not released a patch, the vulnerability is not listed on CISA's Known Exploited Vulnerabilities catalog, and no working exploit has been publicly disclosed.

Technical Analysis

The vulnerability resides in the AVRCP_Br_Response_Parser component of the Sony XAV-9500ES head unit. AVRCP is a Bluetooth profile that allows devices such as smartphones to control media playback on the head unit — track selection, volume, play/pause, and metadata display. The profile operates over an L2CAP channel using a well-defined command/response structure defined by the Bluetooth SIG specification.

The flaw is classified as CWE-122 — a heap-based buffer overflow. The specific mechanism is the lack of proper length validation on user-supplied data before it is copied into a heap-allocated buffer. When the device processes certain AVRCP response packets, the parser fails to verify that the incoming payload length matches the expected buffer size. An incoming AVRCP packet with an oversized or malformed parameter field causes the parser to write beyond the bounds of the destination heap buffer, corrupting adjacent heap metadata or attacker-controlled data structures.

The attack surface is the Bluetooth stack's AVRCP handling path. The attacker does not require any network-level access to the internet or the vehicle's internal network because the attack vector is Bluetooth — a local wireless interface with an adjacent access range (AV:A in the CVSS vector). The pre-authentication requirement is limited to being able to pair a Bluetooth device with the head unit, which typically happens in discoverable/pairable mode and often with default or simple PINs. No special privileges or credentials are needed to trigger the flaw (PR:N), though user interaction (UI:R) is required for pairing to succeed.

The vulnerability class is well understood. Heap-based overflows in protocol parses typically lead to one of three outcomes: (1) a denial-of-service crash if the overflow corrupts critical heap structures indiscriminately, (2) controlled memory corruption with a crafted heap layout, or (3) direct manipulation of function pointers or virtual table entries to redirect execution to attacker-controlled shellcode or ROP chains. In the case of a Bluetooth device parser that frequently receives variable-length data, the attacker has significant control over the length and content of the injected data, making code execution the likely goal.

Attackers need to reverse-engineer the protocol parser to craft the precise packet layout, and possibly need heap-spraying or other heap grooming to achieve reliable exploitation. However, the AV:A vector means the attacker must be physically within Bluetooth range (typically 10-100 meters) of the vehicle.

No function names, API paths, or specific implementation details beyond "AVRCP_Br_Response_Parser" are available in the NVD description, so the exact offset, vulnerable function call, or triggering packet structure cannot be provided.

Exploitation Scenarios

1. Reconnaissance and Target Identification

The attacker must first identify a target vehicle equipped with a Sony XAV-9500ES head unit. This can be done through physical observation (visible head unit model), or by actively scanning for Bluetooth devices advertising the head unit's service class or device name. The attacker would use a Bluetooth-enabled device (e.g., a laptop with a USB Bluetooth adapter or a smartphone with an exploit delivery application) and scan for the XAV-9500ES's MAC address or Bluetooth name. The attacker then places the device in pairing mode.

2. Triggering the Vulnerability

The attacker pairs their malicious Bluetooth device with the head unit. Pairing may use default PINs (often "0000" or "1234" in many car head units) or the user may be tricked via social engineering (e.g., by appearing as a legitimate smartphone) to accept pairing. Once paired, the attacker creates an AVRCP connection — either the central role or peripheral role depending on what the head unit supports. The attacker then sends a crafted AVRCP response packet (e.g., an AV/C response frame for a GetCapabilities, GetElementAttributes, or similar command) where the length field of a parameter or payload is set to a value larger than the heap buffer that the AVRCP_Br_Response_Parser expects to use. The parser copies the oversized payload into the undersized heap buffer without validation, overflowing the buffer boundary.

3. Payload and Execution Method

The attack delivers a heap buffer overflow. The immediate effect is likely a crash of the Bluetooth/AVRCP service. To achieve code execution, the attacker uses a heap-spraying or heap-grooming technique before triggering the overflow to position controlled data in adjacent heap chunks. The overflow data overwrites heap metadata (e.g., chunk headers in the allocator) or adjacent object fields (e.g., function pointers, buffer length fields). On successful exploitation, the attacker redirects control flow and executes shellcode — either in the Bluetooth firmware context or in the head unit's application processor, depending on the internal architecture. The NVD description states the execution occurs "in the context of the device," which implies the head unit's full privilege level.

4. Post-Exploitation Impact

Once code execution is achieved, the attacker can:

• Persist in the device firmware (if flash write access is obtainable)
• Access head unit data (contacts, paired device history, navigation history)
• Manipulate head unit display and audio output — potentially distracting the driver
• Use the head unit as a pivot point to attack other vehicle systems if there are internal network connections (CAN bus, ethernet backbone)
• Exfiltrate sensitive information stored in the head unit

No public exploit code is available, and no active campaigns have been reported. The attack chain above is derived strictly from the vulnerability description and knowledge of the AVRCP profile and heap overflow exploitation techniques.

Impact Assessment

Business and Safety Impact: This vulnerability targets an in-vehicle entertainment system. The primary impact is complete compromise of the device — all CIA properties are affected (C:H, I:H, A:H per the CVSS vector). Given that the vulnerable device is physically part of a vehicle, the impact transcends typical IT security: a compromised head unit can be used to distract the driver, provide false navigation, or potentially pivot into vehicle control systems, though the NVD description indicates only device-context code execution. The psychological and physical safety implications of an attacker having persistent control over a vehicle's primary human-machine interface are severe.

Affected Systems: Sony XAV-9500ES head units. All firmware versions are believed to be affected, as no patch has been identified. No other Sony devices have been reported as vulnerable.

Blast Radius: The attack is limited to Bluetooth range — roughly 10 to 100 meters. However, the attacker can be anonymous and untraceable. The vehicle user will not typically notice that a malicious device has paired — pairing prompts may be bypassed by simple PINs or the user may accept it thinking it is their phone.

CVSS Analysis: CVSS 8.0 (High). The attack vector is Adjacent (AV:A) — Bluetooth. Attack complexity is Low (AC:L) — the parser has no complex input transformations before the overflow. No privileges required (PR:N). User interaction is required (UI:R) because pairing must be accepted. Consequences are rated High for Confidentiality, Integrity, and Availability — the device is fully compromised.

Patch Confidence: 0/4 — no patch evidence from any tracked source. This vulnerability remains unpatched at the time of writing.

Known Exploits: No public PoC, no Nuclei template, no exploit code available. No CISA KEV listing. No threat actor campaigns observed.

Detection Guidance

Sigma Rule

title: Sony XAV-9500ES AVRCP Heap Overflow Exploitation Attempt
id: 23f1a6c2-9ef4-4a48-b9a1-0bd45e61a9d3
status: experimental
description: Detects unusual Bluetooth AVRCP traffic patterns that may indicate heap overflow attempts against Sony XAV-9500ES head units
author: Valtersit Threat Intelligence
date: 2026/01/15
tags:
    - attack.t1190
    - cve.2026.18282
    - cwe.122
logsource:
    product: linux
    service: bluetooth
    category: bluetooth_events
detection:
    selection_avrcp:
        bt_profile: "AVRCP"
        bt_protocol: "L2CAP"
    selection_anomaly:
        frame_size: "> expected"
        packet_length: "> 1024"
    condition: selection_avrcp and selection_anomaly
falsepositives:
    - Legitimate AVRCP media metadata transfers with large album art
level: high

YARA Rule

rule CVE_2026_18282_AVRCP_Overflow_Targeting
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects binaries or firmware blobs containing patterns typical of Sony XAV-9500ES AVRCP heap overflow exploit attempts"
        cve = "CVE-2026-18282"
        reference = "ZDI-CAN-28995"
    strings:
        $s_avrcp_parse = "AVRCP_Br_Response_Parser" ascii wide
        $s_getcap = "GetCapabilities" ascii wide nocontext
        $s_heapprefix = { 48 65 61 70 42 75 66 66 65 72 } // "HeapBuffer"
        $s_shellcode_hint = { 31 C0 50 68 2F 2F 73 68 68 2F 62 69 6E } // typical x86 /bin/sh shellcode prefix
    condition:
        any of ($s_avrcp_parse*) and 2 of ($s_getcap*)
        or (uint16(0) == 0x5A4D and any of ($s_shellcode_hint*) )
}

Suricata IDS Rule

alert bluetooth any any -> any any (msg:"ET EXPLOIT Sony XAV-9500ES AVRCP Heap Overflow Attempt (CVE-2026-18282)"; flow:to_server; content:"|04 09|"; depth:2; content:"|0C 00|"; within:2; content:"|FF FF|"; within:1024; pcre:"/^.{0,4}\x00\x5c\x00\x00/"; classtype:attempted-admin; sid:202618282; rev:1; metadata:created_at 2026_01_15, updated_at 2026_01_15, cve CVE-2026-18282;)

Note: The Suricata rule above is a placeholder — because the actual AVRCP packet structure triggering the overflow is not publicly documented, precise byte-matching isn't possible. A real rule would need to be developed against a captured exploit. The rule demonstrates the structure for a proper AVRCP-specific detection, referencing a L2CAP packet with AVRCP header (AVC command frame with opcode 0x1A) and abnormally large parameter lengths.

Elastic Detection

// Elastic EQL rule — detects anomalous AVRCP processing on Bluetooth stack
sequence by process.name with maxspan=5s
  [ file where event.type == "modification" and process.name == "bluetoothd" and
    process.parent.name == "systemd" ]
  [ network where event.type == "connection" and process.name == "bluetoothd"
    and destination.port == 1  // L2CAP PSM 1 (SDP) — initial connection
    and network.transport == "l2cap" ]
  [ process where event.type == "start" and
    process.name == "bt_parser" and
    process.args == "avrcp_bridge" and
    user.name == "root" ]

Splunk SPL Query

index=linux_bluetooth OR sourcetype=bluetooth_logs
| search "AVRCP" AND ("parser" OR "response" OR "overrun" OR "heap")
  OR "alloc overflow" OR "length error"
| eval severity = case(
    match(_raw, "(?i)heap|(?i)overflow|(?i)overrun"), "HIGH",
    match(_raw, "(?i)error|(?i)fail"), "MEDIUM",
    true(), "LOW")
| where severity = "HIGH"
| table _time, src_ip, dest_ip, process_name, user, message
| dedup process_name, message
| sort - _time

Wazuh OSSEC Rule

<group name="bluetooth,avrcp,cve-2026-18282,">
  <rule id="332386" level="12">
    <decoded_as>json</decoded_as>
    <field name="bluetooth_profile">AVRCP</field>
    <field name="bt_event">pairing_success</field>
    <description>Sony XAV-9500ES: Bluetooth pairing with a new device — possible reconnaissance for CVE-2026-18282</description>
    <group>attack.t1190, gdpr_IV_35.7.d,</group>
  </rule>

  <rule id="332387" level="15">
    <decoded_as>json</decoded_as>
    <field name="bluetooth_profile">AVRCP</field>
    <field name="bt_event">response_parse_error</field>
    <description>Sony XAV-9500ES: AVRCP response parser reported an anomaly — possible heap overflow attempt against CVE-2026-18282</description>
    <group>attack.t1190, cve.2026.18282, cwe.122,</group>
    <mitre>
      <id>T1190</id>
    </mitre>
  </rule>

  <rule id="332388" level="15" frequency="10" timeframe="300">
    <if_matched_sid>1828201</if_matched_sid>
    <description>Sony XAV-9500ES: Repeated Bluetooth pairing attempts — possible active exploitation attempt for CVE-2026-18282</description>
    <group>attack.t1190, cve.2026.18282,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 (UNPATCHED)

The vendor has not released a patch. Sony has not published any advisory, workaround, or firmware update related to CVE-2026-18282 as of this report. No evidence exists of an upcoming fix.

1. IMMEDIATE MITIGATIONS

• Disable Bluetooth pairing when not needed: The attack requires the ability to pair with the head unit. Disabling pairing mode when the user is not actively connecting a new phone significantly narrows the attack window.
• Change Bluetooth PINs: If the device supports a custom PIN for pairing, change from default values ("0000", "1234") to a complex alphanumeric code.
• Remove unused paired devices: Periodically remove all paired devices that are not actively used.
• Do not allow ambient pairing: If the head unit supports "auto-accept pairing" mode, disable it. Require manual acceptance of every pairing request.
• Physical proximity control: Since the attack vector is Bluetooth, maintaining physical awareness of individuals within ~100m of the vehicle reduces the attack surface.
• Operational restriction: If practical, power off the head unit's Bluetooth radio when the vehicle is parked and not in use.

2. PATCH/UPGRADE STEPS

• Monitor vendor channels: Subscribe to Sony's mobile and car audio security advisories. Watch the ZDI advisory (ZDI-CAN-28995) for coordinated disclosure updates.
• Apply firmware updates: When Sony releases a firmware update for the XAV-9500ES that addresses this CVE, apply it immediately. Until then, no patch is available.
• Contact Sony support: Enterprise fleets with XAV-9500ES units should contact their Sony representative for a timeline on a fix.

3. LONG-TERM HARDENING

• Change security architecture: Vehicle head units should treat Bluetooth — a telemetry and entertainment channel — as a hostile network. The AVRCP parser should never be exposed directly to user-adjacent buffers without strict length validation and a dedicated bounds-checking layer.
• Use memory-safe languages: Fragments of the Bluetooth stack implemented in memory-safe languages (Rust, Go) would eliminate this class of vulnerability.
• Sandbox the Bluetooth stack: Run the Bluetooth protocol stack in a restricted execution container, reducing the impact of a compromise from "full device access" to "limited sandbox breakout."
• Network segmentation in the vehicle: Ensure the head unit is isolated from the CAN bus or automotive ethernet backbone such that compromising the head unit does not provide a path to safety-critical systems.
• Fleet management: Enterprise fleets using these head units should develop a decommissioning or replacement plan if a patch does not materialize in a reasonable timeframe.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2026-18282 — Official NVD description and CVSS scoring.
2. ZDI Advisory (ZDI-CAN-28995): The Zero Day Initiative is the reported researcher for this vulnerability. Their advisory, when public, will contain technical details on the discovery. The ZDI identifier is ZDI-CAN-28995.
3. Sony XAV-9500ES Product Page: https://www.sony.com/electronics/in-car-receivers-players/xav-9500es — Vendor product information; monitor for firmware update announcements.
4. Bluetooth AVRCP Specification (Bluetooth SIG): https://www.bluetooth.com/specifications/specs/avrcp-1-6-1/ — Reference for the AVRCP profile protocol structure, useful for researchers developing detection or exploit analysis.
5. CISA KEV (no listing): https://www.cisa.gov/known-exploited-vulnerabilities-catalog — CVE-2026-18282 is not listed; no known exploit-in-the-wild evidence.

Threat Actor Activity: No known threat actor campaigns or exploit-in-the-wild evidence as of January 2026. The EPSS score has not yet been published by FIRST.org.