CVE-2026-19774 in BlueZ
Summary
by MITRE • 09/15/2026
BlueZ A2DP Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of BlueZ. An attacker must first obtain the ability to pair a malicious Bluetooth device with the target system in order to exploit this vulnerability.
The specific flaw exists within the handling of the stream endpoints. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-29429.
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Analysis
by VulDB Data Team • 09/20/2026
The BlueZ implementation, which serves as the primary Bluetooth protocol stack for Linux operating systems, contains a critical security flaw within its Advanced Audio Distribution Profile (A2DP) subsystem. This vulnerability is classified as a stack-based buffer overflow that permits remote code execution under specific network-adjacent conditions. The core of the issue lies in the handling of stream endpoints during audio data transmission processes. When BlueZ receives data packets intended for A2DP streaming, it fails to perform adequate validation checks on the length of user-supplied input before copying this data into a fixed-length buffer located on the application stack. This lack of bounds checking allows an attacker who controls the size or content of the incoming stream to overwrite adjacent memory locations on the stack, potentially overwriting return addresses and control flow pointers with malicious payloads.
Exploitation of this vulnerability requires a specific sequence of actions that limits its immediate applicability in untargeted attacks but significantly increases the severity for targeted scenarios. An attacker must first establish a trusted relationship with the target system by successfully pairing a malicious Bluetooth device with it. This prerequisite implies that the attack is not entirely open to any random observer on the airwaves, as Bluetooth pairing typically involves authentication or user interaction depending on the security mode configured in the operating system. However, once this trust boundary is crossed and the devices are paired, the attacker can trigger the overflow by sending specially crafted A2DP stream data. Because BlueZ often runs with elevated privileges to manage hardware interfaces and audio routing, successful exploitation results in arbitrary code execution within the context of the root user account. This grants the attacker complete control over the affected system, enabling them to install backdoors, exfiltrate sensitive data, or pivot to other systems on the local network.
From a technical classification perspective, this vulnerability aligns with CWE-120, which denotes Buffer Copy without Checking Size of Input, specifically manifesting as a stack-based buffer overflow. The attack vector is categorized under MITRE ATT&CK technique T1563, Remote Service Session Hijacking, due to the requirement of establishing a paired connection before exploitation can occur. Furthermore, the ability to execute code with root privileges maps directly to privilege escalation techniques found in post-exploitation phases. The impact extends beyond simple denial of service; while buffer overflows can sometimes be leveraged for local denial of service through crashes, this specific flaw is designed and proven capable of achieving arbitrary code execution, which represents a catastrophic failure of the system's integrity and confidentiality guarantees.
Mitigation strategies must address both the immediate technical weakness and the broader operational risks associated with Bluetooth connectivity. The primary defense involves applying vendor-provided patches that update the BlueZ stack to include proper length validation before memory copy operations occur within the A2DP stream handling logic. System administrators should ensure that their Linux distributions are configured for automatic security updates or manually verify that the latest stable version of BlueZ is installed. Additionally, reducing the attack surface by disabling Bluetooth when not in use can prevent exploitation attempts entirely. For environments where Bluetooth must remain active, enforcing strict pairing policies and using secure simple pairing with high authentication levels can mitigate the risk of an attacker successfully establishing the required trusted connection. Monitoring for unusual outbound network connections or unexpected privilege escalations may also aid in detecting attempted exploits after a patch has been applied but before full remediation is complete across all endpoints.