CVE-2024-36942 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: qca: fix firmware check error path
A recent commit fixed the code that parses the firmware files before downloading them to the controller but introduced a memory leak in case the sanity checks ever fail.
Make sure to free the firmware buffer before returning on errors.
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Analysis
by VulDB Data Team • 07/09/2026
The vulnerability resides within the Linux kernel's Bluetooth subsystem, specifically in the qca driver component responsible for handling Qualcomm Atheros Bluetooth controllers. This issue represents a classic memory management flaw that occurs during firmware validation processes, where proper resource cleanup fails to occur upon error conditions. The problem emerged from a recent code modification designed to enhance firmware parsing capabilities before downloading to the Bluetooth controller, demonstrating how seemingly beneficial enhancements can introduce security regressions. The vulnerability is categorized as a memory leak in the context of device driver firmware handling, which directly impacts system stability and resource utilization.
The technical flaw manifests when firmware sanity checks fail during the pre-download validation phase, creating a scenario where allocated memory buffers containing firmware data are not properly released back to the system. This memory leak occurs specifically within the error handling path of the firmware parsing function, where the code correctly identifies invalid firmware but fails to execute the necessary cleanup operations. The issue stems from improper resource management practices during exception handling, where developers assumed that successful firmware validation would always occur, leading to oversight in error code paths. According to CWE standards, this represents a memory leak vulnerability classified under CWE-401, specifically related to failure to release memory after it has been allocated.
The operational impact of this vulnerability extends beyond simple resource consumption issues, as persistent memory leaks can degrade system performance over time and potentially lead to system instability or crashes. When multiple firmware validation failures occur, the accumulated memory consumption can exhaust available system resources, particularly affecting embedded systems or devices with limited memory constraints. The vulnerability affects any system running Linux kernel versions that include the problematic commit, impacting a wide range of hardware platforms including smartphones, tablets, laptops, and IoT devices that utilize Qualcomm Atheros Bluetooth controllers. From an attacker perspective, this could enable resource exhaustion attacks or contribute to broader system reliability issues, though it does not directly enable privilege escalation or remote code execution.
Mitigation strategies focus on implementing proper error handling patterns that guarantee memory cleanup regardless of execution path. The fix requires ensuring that firmware buffers are freed before returning from error conditions, which can be achieved through structured programming approaches such as using RAII (Resource Acquisition Is Initialization) patterns or explicit cleanup functions called before every return statement in error paths. System administrators should prioritize applying kernel updates containing the fixed commit to eliminate this vulnerability across affected deployments. The solution aligns with ATT&CK framework concepts related to privilege escalation and resource exhaustion attacks, where proper memory management serves as a fundamental defense mechanism against such threats. Additionally, implementing comprehensive testing of error paths during firmware validation processes can help prevent similar issues in future development cycles, emphasizing the importance of thorough code review procedures for device driver components that handle critical system resources.