CVE-2026-66098 in Mira
Summary
by MITRE • 08/11/2026
The Mira hormone monitor device firmware accepts a 0x01 write from any BLE central without authentication, causing the device to reboot into bootloader mode. An attacker could cause a denial-of-service condition or disrupt ovulation tracking and fertility monitoring workflow.
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Analysis
by VulDB Data Team • 08/12/2026
The vulnerability in question involves a critical security flaw within the firmware of Mira hormone monitor devices that operates at the Bluetooth Low Energy communication layer. This issue stems from an improper access control mechanism that allows any remote BLE central to execute a specific write operation with the value 0x01, bypassing all authentication requirements. The device's firmware lacks proper authorization checks, creating an unauthenticated entry point that directly triggers a system reboot into bootloader mode. This fundamental flaw represents a design weakness in the device's security architecture and falls under the category of insufficient authentication controls as defined by CWE-287.
The technical execution of this vulnerability occurs through the Bluetooth Low Energy protocol stack where an attacker positioned within range can establish a connection to the device and perform a write operation to a specific attribute handle. The firmware implementation fails to validate the identity or authorization status of the connecting central before processing the command, resulting in immediate system state changes that force the device into bootloader mode. This behavior is particularly concerning because it operates at the hardware abstraction layer where such low-level commands should be protected by robust authentication mechanisms and access controls.
The operational impact of this vulnerability extends beyond simple denial-of-service conditions to compromise the core functionality of fertility monitoring services. When the device reboots into bootloader mode, it disrupts the continuous tracking of ovulation patterns that users rely upon for reproductive health management and family planning decisions. The disruption can occur at any time during the monitoring cycle, potentially missing critical fertility windows and rendering the device ineffective for its intended purpose. This vulnerability directly affects user workflows and could lead to unintended pregnancy risks or missed fertility awareness opportunities, making it particularly dangerous in a medical device context where reliability and continuous operation are paramount.
From a cybersecurity perspective, this vulnerability aligns with several ATT&CK framework techniques including T1072 Software Deployment Tools for establishing persistent access points and T1499 Endpoint Termination for disrupting service availability. The lack of authentication controls violates fundamental security principles and creates an attack surface that can be exploited by adversaries without requiring physical access to the device or sophisticated technical skills. Organizations implementing such medical devices should consider this vulnerability in their risk assessments and implement proper firmware security measures including secure boot mechanisms, authenticated command processing, and proper access control implementations.
Mitigation strategies should focus on firmware-level improvements including mandatory authentication for all critical system commands, implementation of secure communication protocols with proper encryption and integrity verification, and enforcement of access control lists that restrict administrative functions to authorized parties only. Device manufacturers should also implement rate limiting and connection monitoring to detect anomalous behavior patterns that could indicate exploitation attempts. The solution requires comprehensive security testing including penetration testing of the BLE interface and validation of authentication mechanisms before deployment in medical environments where device reliability and user safety are critical considerations.