CVE-2022-50716
Unknown Unknown - Not Provided
Use-After-Free in Linux ar5523 WiFi Driver Causes Kernel Crash

Publication date: 2025-12-24

Last updated on: 2025-12-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: ar5523: Fix use-after-free on ar5523_cmd() timed out syzkaller reported use-after-free with the stack trace like below [1]: [ 38.960489][ C3] ================================================================== [ 38.963216][ C3] BUG: KASAN: use-after-free in ar5523_cmd_tx_cb+0x220/0x240 [ 38.964950][ C3] Read of size 8 at addr ffff888048e03450 by task swapper/3/0 [ 38.966363][ C3] [ 38.967053][ C3] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.0.0-09039-ga6afa4199d3d-dirty #18 [ 38.968464][ C3] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014 [ 38.969959][ C3] Call Trace: [ 38.970841][ C3] <IRQ> [ 38.971663][ C3] dump_stack_lvl+0xfc/0x174 [ 38.972620][ C3] print_report.cold+0x2c3/0x752 [ 38.973626][ C3] ? ar5523_cmd_tx_cb+0x220/0x240 [ 38.974644][ C3] kasan_report+0xb1/0x1d0 [ 38.975720][ C3] ? ar5523_cmd_tx_cb+0x220/0x240 [ 38.976831][ C3] ar5523_cmd_tx_cb+0x220/0x240 [ 38.978412][ C3] __usb_hcd_giveback_urb+0x353/0x5b0 [ 38.979755][ C3] usb_hcd_giveback_urb+0x385/0x430 [ 38.981266][ C3] dummy_timer+0x140c/0x34e0 [ 38.982925][ C3] ? notifier_call_chain+0xb5/0x1e0 [ 38.984761][ C3] ? rcu_read_lock_sched_held+0xb/0x60 [ 38.986242][ C3] ? lock_release+0x51c/0x790 [ 38.987323][ C3] ? _raw_read_unlock_irqrestore+0x37/0x70 [ 38.988483][ C3] ? __wake_up_common_lock+0xde/0x130 [ 38.989621][ C3] ? reacquire_held_locks+0x4a0/0x4a0 [ 38.990777][ C3] ? lock_acquire+0x472/0x550 [ 38.991919][ C3] ? rcu_read_lock_sched_held+0xb/0x60 [ 38.993138][ C3] ? lock_acquire+0x472/0x550 [ 38.994890][ C3] ? dummy_urb_enqueue+0x860/0x860 [ 38.996266][ C3] ? do_raw_spin_unlock+0x16f/0x230 [ 38.997670][ C3] ? dummy_urb_enqueue+0x860/0x860 [ 38.999116][ C3] call_timer_fn+0x1a0/0x6a0 [ 39.000668][ C3] ? add_timer_on+0x4a0/0x4a0 [ 39.002137][ C3] ? reacquire_held_locks+0x4a0/0x4a0 [ 39.003809][ C3] ? __next_timer_interrupt+0x226/0x2a0 [ 39.005509][ C3] __run_timers.part.0+0x69a/0xac0 [ 39.007025][ C3] ? dummy_urb_enqueue+0x860/0x860 [ 39.008716][ C3] ? call_timer_fn+0x6a0/0x6a0 [ 39.010254][ C3] ? cpuacct_percpu_seq_show+0x10/0x10 [ 39.011795][ C3] ? kvm_sched_clock_read+0x14/0x40 [ 39.013277][ C3] ? sched_clock_cpu+0x69/0x2b0 [ 39.014724][ C3] run_timer_softirq+0xb6/0x1d0 [ 39.016196][ C3] __do_softirq+0x1d2/0x9be [ 39.017616][ C3] __irq_exit_rcu+0xeb/0x190 [ 39.019004][ C3] irq_exit_rcu+0x5/0x20 [ 39.020361][ C3] sysvec_apic_timer_interrupt+0x8f/0xb0 [ 39.021965][ C3] </IRQ> [ 39.023237][ C3] <TASK> In ar5523_probe(), ar5523_host_available() calls ar5523_cmd() as below (there are other functions which finally call ar5523_cmd()): ar5523_probe() -> ar5523_host_available() -> ar5523_cmd_read() -> ar5523_cmd() If ar5523_cmd() timed out, then ar5523_host_available() failed and ar5523_probe() freed the device structure. So, ar5523_cmd_tx_cb() might touch the freed structure. This patch fixes this issue by canceling in-flight tx cmd if submitted urb timed out.
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Meta Information
Published
2025-12-24
Last Modified
2025-12-24
Generated
2026-05-07
AI Q&A
2025-12-24
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50716
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free bug in the Linux kernel's ar5523 wireless driver. Specifically, if the function ar5523_cmd() times out, the device structure is freed while a callback function ar5523_cmd_tx_cb() might still try to access it, leading to use-after-free. This can cause kernel crashes or undefined behavior. The issue was fixed by canceling in-flight transmit commands if the submitted USB request timed out.


How can this vulnerability impact me? :

This vulnerability can lead to kernel crashes or instability due to use-after-free memory access in the wireless driver. This could potentially be exploited to cause denial of service or other unpredictable behavior on affected systems running the vulnerable Linux kernel.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring the kernel logs for use-after-free errors related to the ar5523 driver. Specifically, look for KASAN (Kernel Address Sanitizer) reports with messages like 'BUG: KASAN: use-after-free in ar5523_cmd_tx_cb'. You can check the kernel log using the command: dmesg | grep ar5523_cmd_tx_cb. Additionally, monitoring for kernel crashes or warnings related to ar5523 may help detect the issue.


What immediate steps should I take to mitigate this vulnerability?

The immediate mitigation step is to apply the patch that fixes the use-after-free issue by canceling in-flight tx commands if the submitted URB times out. Until the patch is applied, consider disabling the ar5523 wireless driver to prevent triggering the vulnerability. Updating the Linux kernel to a version that includes this fix is recommended as the definitive mitigation.


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