CVE-2026-75032 in Red Hat
Summary
by MITRE • 08/18/2026
A flaw was found in BlueZ. Insufficient validation of packet length fields in GetFolderItems responses within the Audio/Video Remote Control Profile (AVRCP) implementation allows a malicious Bluetooth device within range to cause an out-of-bounds memory read. This vulnerability, affecting the parse_media_element() and parse_media_folder() functions, can lead to a crash of the bluetoothd daemon, resulting in a Denial of Service (DoS). It could also potentially expose sensitive heap memory contents. Exploitation requires user interaction to pair with the malicious device.
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Analysis
by VulDB Data Team • 08/18/2026
The vulnerability identified within BlueZ centers on insufficient validation of packet length fields during the processing of GetFolderItems responses in the Audio/Video Remote Control Profile implementation. This flaw specifically impacts the parse_media_element and parse_media_folder functions, which are responsible for parsing metadata from connected audio devices such as headsets or car infotainment systems. When a malicious Bluetooth device sends a crafted response with an invalid packet length field, the parser fails to correctly verify that the data fits within expected bounds before accessing memory locations associated with those fields. This lack of rigorous input validation allows an attacker to trigger an out-of-bounds read operation, where the system attempts to access heap memory addresses beyond the allocated buffer limits defined by the legitimate protocol structure.
From a technical perspective, this issue represents a classic instance of improper input handling leading to memory safety violations. The absence of strict boundary checks means that if the length field indicates more data than is actually present or exceeds internal array limits, the application reads arbitrary heap contents rather than stopping at valid boundaries. This behavior aligns with Common Weakness Enumeration CWE-125, which describes out-of-bounds read vulnerabilities where software reads memory beyond the end of a buffer. In the context of Bluetooth stack implementations like BlueZ, such errors are particularly dangerous because they occur during routine interactions that involve parsing complex metadata structures sent by peripheral devices.
The operational impact of this vulnerability is primarily characterized as a Denial of Service against the bluetoothd daemon process. Upon encountering the malformed packet length field, the application may crash due to segmentation faults or other memory access violations triggered by the out-of-bounds read. This results in the immediate termination of the Bluetooth service on the host system, effectively disabling all Bluetooth functionality until the service is manually restarted or the device is rebooted. For users relying on continuous connectivity for audio streaming, hands-free calling, or peripheral management, this disruption can be significant and inconvenient.
Beyond simple availability impact, there exists a secondary risk regarding information disclosure. The out-of-bounds read operation may expose sensitive contents of heap memory to the attacker via the malformed response mechanism if the protocol allows returning parsed data back over the air interface in certain error handling paths or debug modes. Although exploitation typically requires user interaction because the victim must pair with the malicious device, this requirement does not eliminate the threat entirely. Attackers can social engineer victims into pairing with rogue devices disguised as legitimate peripherals, thereby gaining a foothold to trigger the vulnerability and potentially leak memory contents that could contain cryptographic keys, session tokens, or other private data stored in adjacent heap regions.
This vulnerability maps closely to MITRE ATT&CK technique T1059, specifically command scripting or system commands if further exploitation leads to code execution, though currently it is primarily classified under reconnaissance or initial access vectors involving Bluetooth protocols. It also relates to CWE-20 regarding improper input validation and CWE-787 for out-of-bounds write/read scenarios depending on the exact memory state at time of crash. The requirement for pairing means that standard security controls like MAC filtering might offer some mitigation, but they are not foolproof against determined attackers who can spoof authorized addresses or exploit user trust in familiar device names.
To mitigate this risk, system administrators and users should ensure that BlueZ is updated to the latest stable version where these parsing functions have been patched with rigorous length checks before memory access occurs. Additionally, disabling automatic pairing for unknown devices reduces the attack surface by preventing untrusted peripherals from establishing the necessary connection state required to send malicious GetFolderItems responses. Users should also be cautious when accepting pairing requests from unfamiliar Bluetooth accessories and consider using device whitelisting features available in modern operating systems to restrict connections only to known, trusted hardware. Regular auditing of connected devices and monitoring for unexpected bluetoothd crashes can help detect potential exploitation attempts early.