CVE-2023-20987 in Android
Summary
by MITRE • 03/24/2023
In btm_read_link_quality_complete of btm_acl.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure over Bluetooth with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-13Android ID: A-260569414
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Analysis
by VulDB Data Team • 09/07/2025
The vulnerability identified as CVE-2023-20987 resides within the Bluetooth stack implementation of Android 13 systems, specifically within the btm_read_link_quality_complete function located in the btm_acl.cc source file. This issue represents a classic out-of-bounds read condition that occurs when the system fails to validate array indices before accessing memory locations. The flaw manifests during Bluetooth link quality reporting operations where the system processes completed link quality information without proper boundary validation, creating a potential attack surface for information disclosure.
The technical implementation of this vulnerability stems from insufficient input validation within the Bluetooth management layer of Android's core system. When the btm_read_link_quality_complete function processes incoming Bluetooth link quality data, it assumes that the data structure contains valid indices and bounds without performing necessary checks. This missing bounds check allows an attacker with system-level privileges to craft malicious Bluetooth packets that can trigger memory access violations. The vulnerability specifically impacts the Bluetooth low energy (BLE) and classic Bluetooth protocols that operate within the Android Bluetooth subsystem.
From an operational perspective, exploitation of CVE-2023-20987 requires an attacker to possess system execution privileges, meaning they must already have elevated access to the device. This prerequisite significantly limits the attack surface but does not eliminate the risk entirely, as local privilege escalation attacks or pre-existing system compromises could potentially leverage this vulnerability. The information disclosure impact could expose sensitive Bluetooth connection data, including link quality metrics, device identifiers, and potentially other system information that could aid in further attacks. This vulnerability aligns with CWE-129, which specifically addresses insufficient validation of array indices, and represents a direct violation of secure coding practices for memory safety.
The attack vector for this vulnerability requires local system access, making it less immediately dangerous than remote exploits but still concerning for devices that may be compromised through other attack vectors. The Android security model typically requires system-level privileges for Bluetooth operations, which means that exploitation would likely occur in environments where an attacker has already gained root access or has equivalent privileges. This vulnerability contributes to the broader category of Bluetooth protocol implementation flaws that have been documented in various ATT&CK framework techniques related to privilege escalation and information gathering. The impact is particularly significant in enterprise environments where Bluetooth connectivity is heavily utilized for device management and IoT integration.
Mitigation strategies for CVE-2023-20987 should focus on implementing proper bounds checking within the Bluetooth management layer and ensuring that all array accesses are validated against their declared bounds. Android security patches typically address such issues by adding validation checks in the affected source code, specifically within the btm_acl.cc file where the function operates. System administrators should prioritize applying the latest Android security updates that contain fixes for this vulnerability, as these patches typically include enhanced input validation and memory safety checks. Additionally, organizations should implement monitoring for unusual Bluetooth activity patterns that could indicate exploitation attempts, particularly in environments where Bluetooth is actively used for device communication. The vulnerability demonstrates the importance of applying defensive programming practices and adhering to secure coding standards that prevent common memory safety issues in system-level code.