CVE-2021-47031 in Linux
Summary
by MITRE • 02/28/2024
In the Linux kernel, the following vulnerability has been resolved:
mt76: mt7921: fix memory leak in mt7921_coredump_work
Fix possible memory leak in mt7921_coredump_work.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/14/2024
The vulnerability identified as CVE-2021-47031 affects the Linux kernel's mt76 wireless driver subsystem, specifically within the mt7921 chipset implementation. This issue resides in the memory management functions responsible for handling core dump operations in wireless network adapters. The mt7921 is a popular wireless chipset used in various networking devices including routers and access points that rely on the Linux kernel's wireless subsystem for proper operation. The vulnerability manifests as a memory leak during the execution of core dump work functions, which are critical for system diagnostics and error reporting in wireless networking hardware.
The technical flaw occurs within the mt7921_coredump_work function where memory allocation occurs without proper corresponding deallocation in certain error paths or execution scenarios. This represents a classic memory management issue that falls under the CWE-401 category of Unchecked Return Value to NULL, where allocated memory resources are not properly released when the system encounters exceptional conditions or error states during core dump processing. The flaw specifically affects the wireless driver's ability to maintain proper memory hygiene during diagnostic operations, potentially leading to gradual memory exhaustion over time as the system continues to process wireless network events.
The operational impact of this vulnerability extends beyond simple resource consumption issues, as it can lead to system instability and performance degradation in wireless networking environments. When memory leaks accumulate over time, they can cause the system to experience reduced performance, increased latency in wireless operations, or even complete system crashes in severe cases. Network administrators managing wireless infrastructure using affected mt7921 chipsets may observe gradual degradation in network performance or unexpected system behavior, particularly in high-traffic wireless environments where core dump operations are more frequent. This vulnerability particularly affects systems where wireless networking is heavily utilized and where diagnostic functionality is regularly exercised.
Mitigation strategies for CVE-2021-47031 should prioritize applying the official kernel patch that resolves the memory leak in the mt7921_coredump_work function. System administrators should ensure their Linux kernel versions include the fix from the upstream kernel repository, typically found in kernel versions 5.14 and later. The patch implements proper memory deallocation routines that ensure all allocated resources are freed regardless of execution path or error conditions. Organizations should also consider implementing monitoring solutions to track memory usage patterns in wireless networking systems, as this can help detect early signs of memory leak accumulation. Additionally, regular system updates and patch management procedures should be enforced to maintain protection against similar vulnerabilities in the wireless driver subsystem, following ATT&CK framework tactics related to privilege escalation and defense evasion through proper system maintenance. The fix aligns with industry best practices for memory management in kernel space drivers and addresses the fundamental issue of resource leak prevention in wireless networking hardware drivers.