Executive Summary

This vulnerability is an out-of-bounds read in the Apache NimBLE HCI H4 driver. It occurs when a specially crafted Bluetooth HCI event causes the driver to read memory outside its intended bounds, potentially leading to invalid memory access. Exploitation requires a compromised or malicious Bluetooth controller sending malformed events. The issue affects Apache NimBLE versions up to 1.8 and is fixed in version 1.9. [1, 2]

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Impact Analysis

The impact of this vulnerability is considered low because it requires a broken or malicious Bluetooth controller to exploit. If exploited, it could cause invalid memory reads which might lead to application instability or crashes, but it does not directly allow code execution or data corruption. Users should upgrade to Apache NimBLE version 1.9 to mitigate this issue. [1]

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Detection Guidance

This vulnerability requires a broken or malicious Bluetooth controller sending specially crafted HCI events to trigger an out-of-bounds read in the Apache NimBLE HCI H4 driver. Detection would involve monitoring Bluetooth HCI traffic for abnormal or malformed HCI events that exceed expected sizes. Since the vulnerability is in the H4 event parsing logic, you can capture Bluetooth HCI traffic using tools like 'btmon' or 'hcidump' on Linux to analyze event sizes. However, no specific detection commands or signatures are provided in the available resources. [1, 2]

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Mitigation Strategies

The immediate mitigation step is to upgrade Apache NimBLE to version 1.9 or later, where the vulnerability has been fixed by adding bounds checking on HCI event sizes to prevent out-of-bounds reads. Since exploitation requires a compromised or bogus Bluetooth controller, limiting Bluetooth device pairing to trusted devices and disabling Bluetooth when not needed can also reduce risk. [1, 2]

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