CVE-2026-68363: Linux kernel · wifi: ath9k: hif_usb: don't dereference hif_dev after re-arming firmware request
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in dad9f96945d77ecd4708f730c06ef54dcd8cc057 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:19 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in dad9f96945d77ecd4708f730c06ef54dcd8cc057, 063497cc9f320ab71a7a937c3bc0a23e630aefe2, 48de0c6952192b0771fca468df4364d11ec74ad9 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: wifi: ath9k: hif_usb: don't dereference hif_dev after re-arming firmware request ath9k_hif_request_firmware() re-arms an asynchronous firmware load via request_firmware_nowait(), passing hif_dev as the completion context, and then still dereferences hif_dev: dev_info(&hif_dev->udev->dev, "ath9k_htc: Firmware %s requested\n", hif_dev->fw_name); The re-armed callback ath9k_hif_usb_firmware_cb() runs on the "events" workqueue and, when the firmware is missing, walks the retry chain into ath9k_hif_usb_firmware_fail() -> complete_all(&hif_dev->fw_done). That releases the wait_for_completion(&hif_dev->fw_done) in a concurrent ath9k_hif_usb_disconnect(), which then kfree()s hif_dev. The trailing dev_info() in the frame that re-armed the request can therefore read freed memory (hif_dev->udev, the first field of struct hif_device_usb): BUG: KASAN: slab-use-after-free in ath9k_hif_request_firmware Read of size 8 ... by task kworker/... ath9k_hif_request_firmware ath9k_hif_usb_firmware_cb drivers/net/wireless/ath/ath9k/hif_usb.c:1247 request_firmware_work_func Allocated by ...: ath9k_hif_usb_probe drivers/net/wireless/ath/ath9k/hif_usb.c Freed by ...: ath9k_hif_usb_disconnect -> kfree drivers/net/wireless/ath/ath9k/hif_usb.c The fw_done barrier only makes disconnect wait for the firmware chain to *terminate*; it does not protect the outer ath9k_hif_request_firmware() frame that re-armed the request and keeps touching hif_dev afterwards. Drop the post-request dev_info(): it is the only use of hif_dev after the async request is armed, and it is purely informational (the dev_err() on the failure path runs only when request_firmware_nowait() did not arm a callback, so hif_dev is still alive there). This was first reported by syzbot as a single, non-reproduced crash that was later auto-obsoleted, and was independently rediscovered by the reFuzz fuzzer, which produced a C reproducer (USB-gadget connect/disconnect of an ath9k_htc device whose firmware download fails). The vulnerable code is unchanged and still present in v7.1-rc6, where the slab-use-after-free reproduces under KASAN once the (sub-microsecond) race window is widened.
References
- git.kernel.org/stable/c/47ed81aaa7f94d9808f4719e78a760c2ec1e6c86 (opens in a new tab)
- git.kernel.org/stable/c/48de0c6952192b0771fca468df4364d11ec74ad9 (opens in a new tab)
- git.kernel.org/stable/c/063497cc9f320ab71a7a937c3bc0a23e630aefe2 (opens in a new tab)
- git.kernel.org/stable/c/7f184ca38a90889f3f6665ff96748b95da39dbee (opens in a new tab)
- git.kernel.org/stable/c/10b0ce629123a3737b4eda50188f73bb7be7b68b (opens in a new tab)
- git.kernel.org/stable/c/48a69cedde7388294e4ea6fd804156cd62bc04fc (opens in a new tab)
- git.kernel.org/stable/c/7c9046d92c4b9789c9d9d775e4fd5f34be64cb0a (opens in a new tab)
- git.kernel.org/stable/c/dad9f96945d77ecd4708f730c06ef54dcd8cc057 (opens in a new tab)