CVE-2022-50881
Unknown Unknown - Not Provided
Use-After-Free in Linux ath9k USB Driver Causes Kernel Crash

Publication date: 2025-12-30

Last updated on: 2025-12-30

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: ath9k: Fix use-after-free in ath9k_hif_usb_disconnect() This patch fixes a use-after-free in ath9k that occurs in ath9k_hif_usb_disconnect() when ath9k_destroy_wmi() is trying to access 'drv_priv' that has already been freed by ieee80211_free_hw(), called by ath9k_htc_hw_deinit(). The patch moves ath9k_destroy_wmi() before ieee80211_free_hw(). Note that urbs from the driver should be killed before freeing 'wmi' with ath9k_destroy_wmi() as their callbacks will access 'wmi'. Found by a modified version of syzkaller. ================================================================== BUG: KASAN: use-after-free in ath9k_destroy_wmi+0x38/0x40 Read of size 8 at addr ffff8881069132a0 by task kworker/0:1/7 CPU: 0 PID: 7 Comm: kworker/0:1 Tainted: G O 5.14.0+ #131 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Workqueue: usb_hub_wq hub_event Call Trace: dump_stack_lvl+0x8e/0xd1 print_address_description.constprop.0.cold+0x93/0x334 ? ath9k_destroy_wmi+0x38/0x40 ? ath9k_destroy_wmi+0x38/0x40 kasan_report.cold+0x83/0xdf ? ath9k_destroy_wmi+0x38/0x40 ath9k_destroy_wmi+0x38/0x40 ath9k_hif_usb_disconnect+0x329/0x3f0 ? ath9k_hif_usb_suspend+0x120/0x120 ? usb_disable_interface+0xfc/0x180 usb_unbind_interface+0x19b/0x7e0 ? usb_autoresume_device+0x50/0x50 device_release_driver_internal+0x44d/0x520 bus_remove_device+0x2e5/0x5a0 device_del+0x5b2/0xe30 ? __device_link_del+0x370/0x370 ? usb_remove_ep_devs+0x43/0x80 ? remove_intf_ep_devs+0x112/0x1a0 usb_disable_device+0x1e3/0x5a0 usb_disconnect+0x267/0x870 hub_event+0x168d/0x3950 ? rcu_read_lock_sched_held+0xa1/0xd0 ? hub_port_debounce+0x2e0/0x2e0 ? check_irq_usage+0x860/0xf20 ? drain_workqueue+0x281/0x360 ? lock_release+0x640/0x640 ? rcu_read_lock_sched_held+0xa1/0xd0 ? rcu_read_lock_bh_held+0xb0/0xb0 ? lockdep_hardirqs_on_prepare+0x273/0x3e0 process_one_work+0x92b/0x1460 ? pwq_dec_nr_in_flight+0x330/0x330 ? rwlock_bug.part.0+0x90/0x90 worker_thread+0x95/0xe00 ? __kthread_parkme+0x115/0x1e0 ? process_one_work+0x1460/0x1460 kthread+0x3a1/0x480 ? set_kthread_struct+0x120/0x120 ret_from_fork+0x1f/0x30 The buggy address belongs to the page: page:ffffea00041a44c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106913 flags: 0x200000000000000(node=0|zone=2) raw: 0200000000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 3, migratetype Unmovable, gfp_mask 0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), pid 7, ts 38347963444, free_ts 41399957635 prep_new_page+0x1aa/0x240 get_page_from_freelist+0x159a/0x27c0 __alloc_pages+0x2da/0x6a0 alloc_pages+0xec/0x1e0 kmalloc_order+0x39/0xf0 kmalloc_order_trace+0x19/0x120 __kmalloc+0x308/0x390 wiphy_new_nm+0x6f5/0x1dd0 ieee80211_alloc_hw_nm+0x36d/0x2230 ath9k_htc_probe_device+0x9d/0x1e10 ath9k_htc_hw_init+0x34/0x50 ath9k_hif_usb_firmware_cb+0x25f/0x4e0 request_firmware_work_func+0x131/0x240 process_one_work+0x92b/0x1460 worker_thread+0x95/0xe00 kthread+0x3a1/0x480 page last free stack trace: free_pcp_prepare+0x3d3/0x7f0 free_unref_page+0x1e/0x3d0 device_release+0xa4/0x240 kobject_put+0x186/0x4c0 put_device+0x20/0x30 ath9k_htc_disconnect_device+0x1cf/0x2c0 ath9k_htc_hw_deinit+0x26/0x30 ath9k_hif_usb_disconnect+0x2d9/0x3f0 usb_unbind_interface+0x19b/0x7e0 device_release_driver_internal+0x44d/0x520 bus_remove_device+0x2e5/0x5a0 device_del+0x5b2/0xe30 usb_disable_device+0x1e3/0x5a0 usb_disconnect+0x267/0x870 hub_event+0x168d/0x3950 process_one_work+0x92b/0x1460 Memory state around the buggy address: ffff888106913180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888106913200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888 ---truncated---
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Meta Information
Published
2025-12-30
Last Modified
2025-12-30
Generated
2026-05-06
AI Q&A
2025-12-30
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50881
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
ath ath9k *
Helpful Resources
Exploitability
CWE
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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 ath9k wireless driver. It occurs in the function ath9k_hif_usb_disconnect() when ath9k_destroy_wmi() tries to access 'drv_priv', which has already been freed by ieee80211_free_hw(). The issue arises because the order of operations was incorrect, leading to access of freed memory. The patch fixes this by moving ath9k_destroy_wmi() before ieee80211_free_hw(), ensuring that memory is not accessed after being freed.


How can this vulnerability impact me? :

This use-after-free vulnerability can lead to undefined behavior such as system crashes, memory corruption, or potential escalation of privileges if exploited. It affects the stability and security of systems using the ath9k wireless driver, potentially causing denial of service or allowing attackers to execute arbitrary code.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, update the Linux kernel to a version that includes the patch fixing the use-after-free in ath9k_hif_usb_disconnect(). The patch moves ath9k_destroy_wmi() before ieee80211_free_hw() to prevent accessing freed memory. Additionally, ensure that urbs from the driver are killed before freeing 'wmi' with ath9k_destroy_wmi() as their callbacks will access 'wmi'.


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