CVE-2022-50829 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath9k: hif_usb: Fix use-after-free in ath9k_hif_usb_reg_in_cb()
It is possible that skb is freed in ath9k_htc_rx_msg(), then usb_submit_urb() fails and we try to free skb again. It causes use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes NULL but rx_buf is not freed and there can be a memory leak.
The patch removes unnecessary nskb and makes skb processing more clear: it is supposed that ath9k_htc_rx_msg() either frees old skb or passes its managing to another callback function.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability CVE-2022-50829 represents a critical use-after-free condition in the Linux kernel's ath9k wireless driver implementation, specifically within the hif_usb subsystem. This flaw exists in the ath9k_hif_usb_reg_in_cb() function where improper memory management leads to potential system instability and security risks. The issue manifests when the wireless driver processes received USB messages through the ath9k_htc_rx_msg() function, creating a scenario where the same memory buffer can be accessed after it has been freed, violating fundamental memory safety principles that are essential for kernel stability and security.
The technical implementation of this vulnerability stems from a race condition in the USB message processing pipeline where the skb (socket buffer) memory allocation and deallocation logic becomes inconsistent. When ath9k_htc_rx_msg() frees an skb buffer and subsequently usb_submit_urb() fails, the code attempts to free the same skb buffer again, resulting in the use-after-free condition. Additionally, the patch reveals another memory leak vulnerability where if alloc_skb() fails during the process, the urb->context becomes NULL but rx_buf memory is not properly freed, creating a memory leak that can accumulate over time and potentially lead to system resource exhaustion. This dual nature of the vulnerability demonstrates poor error handling and memory management practices within the wireless driver's USB communication layer.
The operational impact of CVE-2022-50829 extends beyond simple system crashes, as it can potentially enable privilege escalation attacks through controlled memory corruption. Attackers could exploit this vulnerability to execute arbitrary code within kernel space, leveraging the use-after-free condition to manipulate kernel memory structures and potentially gain elevated privileges. The vulnerability affects systems running Linux kernels with the ath9k wireless driver, particularly those using USB-based wireless adapters from Atheros chipset manufacturers. This aligns with CWE-416, which specifically addresses use-after-free vulnerabilities, and represents a classic example of improper resource management that can lead to memory corruption issues. The vulnerability's discovery through the Linux Verification Center using Syzkaller highlights its significance as an automated testing tool identified security flaw that could be exploited in the wild.
Mitigation strategies for CVE-2022-50829 primarily involve applying the official kernel patch that removes the unnecessary nskb variable and clarifies the skb processing logic to ensure that each skb is either freed by ath9k_htc_rx_msg() or passed to another callback function for proper management. This approach aligns with ATT&CK technique T1068 by preventing the exploitation of kernel memory corruption vulnerabilities. System administrators should prioritize kernel updates and ensure that wireless drivers are current with the latest security patches. Additionally, implementing proper memory management practices and error handling in kernel modules can help prevent similar vulnerabilities from emerging in other driver implementations. Organizations should consider monitoring for unusual network behavior or system crashes that might indicate exploitation attempts, as the vulnerability could be leveraged for persistent access to affected systems through kernel-level privilege escalation.