CVE-2019-8922 in BlueZ
Summary
by MITRE • 11/29/2021
A heap-based buffer overflow was discovered in bluetoothd in BlueZ through 5.48. There isn't any check on whether there is enough space in the destination buffer. The function simply appends all data passed to it. The values of all attributes that are requested are appended to the output buffer. There are no size checks whatsoever, resulting in a simple heap overflow if one can craft a request where the response is large enough to overflow the preallocated buffer. This issue exists in service_attr_req gets called by process_request (in sdpd-request.c), which also allocates the response buffer.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability identified as CVE-2019-8922 represents a critical heap-based buffer overflow in the bluetoothd component of BlueZ versions through 5.48. This flaw resides within the Service Discovery Protocol (SDP) implementation where the system fails to perform any validation of buffer boundaries during data processing. The vulnerability manifests when the service_attr_req function processes incoming requests, specifically within the sdpd-request.c module where response buffers are preallocated but lack any size validation mechanisms. The absence of input sanitization allows malicious actors to craft specially crafted requests that deliberately exceed the allocated buffer boundaries, creating a condition where data is written beyond the intended memory allocation.
The technical implementation of this vulnerability follows a straightforward yet dangerous pattern where the system simply appends all requested attribute values to an output buffer without verifying whether sufficient space exists for the operation. This approach directly violates fundamental security principles of input validation and buffer management, creating an exploitable condition that can be leveraged by attackers with network access to the target system. The flaw is particularly concerning because it occurs in a core system daemon responsible for Bluetooth protocol handling, making it accessible to potential attackers who can send malicious SDP requests over Bluetooth networks. The vulnerability's exploitation potential is significantly enhanced by the fact that the buffer overflow occurs in heap memory, which can lead to arbitrary code execution, memory corruption, or system instability.
The operational impact of CVE-2019-8922 extends beyond simple memory corruption to potentially enable remote code execution and system compromise. When an attacker successfully triggers this vulnerability, they can manipulate heap memory structures to overwrite critical data or function pointers, potentially leading to privilege escalation or complete system takeover. The vulnerability affects systems running BlueZ versions up to 5.48, which represents a substantial portion of deployed Bluetooth implementations across various operating systems including Linux distributions and embedded systems. This flaw aligns with CWE-121, heap-based buffer overflow, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands on affected systems. The vulnerability's presence in a system daemon makes it particularly dangerous as it can be exploited without requiring physical access to the device, and the impact extends to any application or service that relies on Bluetooth connectivity for communication.
Mitigation strategies for CVE-2019-8922 primarily focus on immediate patching of affected BlueZ versions, with the release of BlueZ 5.49 and subsequent versions containing the necessary fixes. System administrators should implement network segmentation to limit Bluetooth access to trusted environments and disable unnecessary Bluetooth services when not actively required. Additional protective measures include monitoring network traffic for unusual SDP request patterns and implementing intrusion detection systems that can identify potential exploitation attempts. The vulnerability demonstrates the critical importance of input validation in system components handling network requests and highlights the necessity of following secure coding practices that prevent buffer overflows through proper bounds checking and memory management. Organizations should also consider implementing application whitelisting and privilege separation to minimize the potential impact of successful exploitation attempts, as the vulnerability can potentially be leveraged to gain elevated privileges within affected systems.