CVE-2026-86919: 
macOS vulnerability analysis and mitigation

CVE-2026-86919 is a stack overflow vulnerability in Apple's Core Bluetooth framework that allows an attacker with a paired Bluetooth device to execute arbitrary code. It affects iOS and iPadOS (before 26.7 and before 27), macOS Sequoia (before 15.8), macOS Tahoe (before 26.7), macOS Golden Gate (before 27), and visionOS (before 27). The vulnerability was discovered by Mathis Mansière and disclosed by Apple on October 19–20, 2026. A CVSS base score has not yet been formally published, though Feedly estimates the severity as HIGH (Apple iOS 27 Advisory, Apple iOS 26.7 Advisory, GitHub Advisory).

The vulnerability is a stack overflow (CWE-121) in Apple's Core Bluetooth framework, specifically in the processing of input received from a paired Bluetooth device. Insufficient input validation allows malformed data from a paired device to overflow the stack, potentially overwriting return addresses or control-flow data to redirect execution. Exploitation requires that the attacker already control a Bluetooth device that is paired with the target — meaning physical proximity and prior pairing are preconditions. Apple addressed the issue with improved input validation. No public proof-of-concept or detailed technical write-up has been published as of the disclosure date (Apple iOS 27 Advisory, Apple macOS Golden Gate Advisory, Feedly).

Successful exploitation allows an attacker with a paired Bluetooth device to execute arbitrary code with the privileges of the Core Bluetooth stack or system process on the affected device. This could lead to full device compromise, unauthorized access to sensitive user data, installation of malware, or further lateral movement within a network environment. The vulnerability affects a broad range of Apple hardware across iOS, iPadOS, macOS, and visionOS platforms (Apple iOS 26.7 Advisory, Apple visionOS 27 Advisory, Feedly).

As of the disclosure date, there is no public proof-of-concept exploit and no evidence of in-the-wild exploitation. The EPSS score is reported as 0.0, and the vulnerability has not been added to CISA's Known Exploited Vulnerabilities catalog. Exploitation requires physical proximity and a previously paired Bluetooth device, which significantly limits the attacker pool compared to fully remote vulnerabilities (Feedly).

1. Prerequisite — Pair a Bluetooth device: The attacker must have a Bluetooth device already paired with the target Apple device (iPhone, iPad, Mac, or Apple Vision Pro). This may be achieved through social engineering, physical access, or exploitation of a separate Bluetooth pairing vulnerability.
2. Craft malformed Bluetooth input: Using a custom Bluetooth stack or modified firmware on the attacker-controlled device, craft a malformed data payload designed to overflow the stack buffer in Apple's Core Bluetooth processing code.
3. Trigger the stack overflow: Transmit the malformed payload to the target device over the Bluetooth connection. The Core Bluetooth framework processes the input without adequate bounds checking, causing a stack overflow.
4. Achieve code execution: By carefully controlling the overflow data (e.g., overwriting the return address with a ROP gadget or shellcode pointer), the attacker redirects execution flow to attacker-controlled code, achieving arbitrary code execution with the privileges of the Bluetooth process (Apple iOS 27 Advisory, Feedly).

• Network/Bluetooth: Unexpected or anomalous Bluetooth communication from a paired device, particularly large or malformed attribute/data packets.
• Logs: Crash logs or system logs referencing Core Bluetooth (bluetoothd) process crashes or unexpected terminations; stack corruption-related crash reports in /Library/Logs/DiagnosticReports/ or device crash logs.
• Process: Unusual child processes spawned by bluetoothd; unexpected network connections initiated by the Bluetooth daemon after a device interaction.
• File System: Unexpected new files, launch agents, or daemons created shortly after a Bluetooth device interaction, potentially indicating post-exploitation persistence.

Apple has released patches addressing this vulnerability in iOS 26.7, iPadOS 26.7, iOS 27, iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, and visionOS 27. Users should update their devices to these versions immediately. As interim mitigations, users should disable Bluetooth when not in use, unpair any untrusted or unrecognized Bluetooth devices, and restrict Bluetooth pairing to known, trusted devices only (Apple iOS 26.7 Advisory, Apple macOS Tahoe Advisory, Apple visionOS 27 Advisory).

Apple credited Mathis Mansière for discovering and reporting the vulnerability, and the entry was added to Apple's security advisories on October 19, 2026. No significant independent researcher commentary, media coverage, or notable social media discussion has been identified beyond standard vulnerability tracking and aggregation sites as of the disclosure date (Apple iOS 27 Advisory, GitHub Advisory).