CVE-2025-68657: ESP-IDF USB Host Use-After-Free Flaw

CVE-2025-68657 Overview

A double free vulnerability exists in the Espressif ESP-IDF USB Host HID (Human Interface Device) Driver in versions prior to 1.1.0. The vulnerability occurs when calls to hid_host_device_close() can free the same usb_transfer_t structure twice. This condition arises because the USB event callback and user code share the hid_iface_t state without proper locking mechanisms, allowing both execution paths to tear down a READY interface simultaneously. This race condition corrupts heap metadata inside the ESP USB host stack, potentially leading to arbitrary code execution or system compromise.

Critical Impact

Physical attackers with USB access can exploit this double free vulnerability to corrupt heap metadata, potentially achieving code execution on ESP-IDF based devices through malicious HID device interactions.

Affected Products

• Espressif ESP-IDF USB Host HID Driver versions prior to 1.1.0
• ESP-USB components utilizing the vulnerable HID driver
• IoT devices and embedded systems built on affected ESP-IDF versions

Discovery Timeline

• 2026-01-12 - CVE-2025-68657 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2025-68657

Vulnerability Analysis

This vulnerability is classified as CWE-415 (Double Free), a memory corruption flaw that occurs when the same memory is freed more than once. In the context of the ESP-IDF USB Host HID driver, the issue manifests due to improper synchronization between the USB event callback mechanism and user-space code paths.

The core problem lies in the shared access to the hid_iface_t structure without adequate locking primitives. When an HID device is in READY state, both the internal USB event handler and external application code can simultaneously attempt to close or tear down the interface. This creates a classic race condition where both paths proceed to call hid_host_device_close(), resulting in the same usb_transfer_t structure being freed twice.

The double free corrupts the heap metadata maintained by the ESP USB host stack's memory allocator. Attackers with physical access could potentially craft malicious HID devices that trigger specific timing conditions to exploit this vulnerability, potentially achieving code execution on the target device.

Root Cause

The root cause is the absence of proper synchronization mechanisms (mutexes, spinlocks, or atomic operations) protecting the hid_iface_t state transitions. The USB event callback and user code operate concurrently on shared state, violating thread safety requirements. When both execution contexts detect a READY interface that needs teardown, they independently proceed with cleanup operations, including freeing the usb_transfer_t buffer, without coordinating their actions.

Attack Vector

This vulnerability requires physical access to the target device (attack vector: Physical) with high attack complexity. An attacker would need to:

1. Gain physical access to a USB port on the vulnerable ESP-IDF device
2. Connect a malicious or specially crafted HID device
3. Trigger the race condition by manipulating USB connection/disconnection timing
4. Exploit the heap corruption to achieve code execution or denial of service

The physical access requirement and timing-dependent nature of the race condition increase the attack complexity. However, successful exploitation could result in complete compromise of confidentiality, integrity, and availability on the affected device.

Detection Methods for CVE-2025-68657

Indicators of Compromise

• Unexpected device crashes or reboots during HID device connection/disconnection events
• Heap corruption errors or memory allocation failures in ESP-IDF system logs
• Abnormal USB enumeration patterns or repeated HID device reconnection attempts
• System instability when using USB HID peripherals such as keyboards or mice

Detection Strategies

• Monitor ESP-IDF device logs for heap corruption warnings or double free detection messages
• Implement USB device allowlisting to detect unauthorized HID device connections
• Deploy firmware integrity monitoring to detect exploitation attempts
• Enable heap debugging features in development environments to catch memory corruption early

Monitoring Recommendations

• Enable verbose logging for the USB host stack to capture device enumeration and teardown events
• Implement watchdog timers to detect and recover from crash loops that may indicate exploitation attempts
• Monitor for unusual patterns in HID device plug/unplug events that could indicate timing attacks
• Consider implementing USB port access controls on production devices

How to Mitigate CVE-2025-68657

Immediate Actions Required

• Upgrade the ESP-IDF USB Host HID component to version 1.1.0 or later immediately
• Review all deployed ESP-IDF devices for vulnerable firmware versions
• Restrict physical USB access to affected devices where possible
• Consider disabling USB HID functionality on devices where it is not required

Patch Information

Espressif has addressed this vulnerability in version 1.1.0 of the USB Host HID component. The fix introduces proper locking mechanisms to synchronize access to the hid_iface_t state between the USB event callback and user code, preventing the race condition that leads to double free.

For technical details on the fix, refer to the GitHub commit and the official changelog. Additional information is available in the GitHub Security Advisory GHSA-gp8r-qjfr-gqfv.

Workarounds

• Physically secure USB ports on affected devices to prevent unauthorized HID device connections
• Implement application-level checks to serialize HID device operations where possible
• Disable USB HID functionality entirely if not required for device operation
• Deploy network segmentation to isolate vulnerable IoT devices from critical infrastructure

# Update ESP-IDF USB Host HID component to patched version
idf.py add-dependency "espressif/usb_host_hid>=1.1.0"

# Verify component version in project
idf.py show-component espressif/usb_host_hid

# Rebuild firmware with updated component
idf.py build