In the Linux kernel, the following vulnerability has been resolved:

wifi: ath9k: hif_usb: fix memory leak of remain_skbs

hif_dev->remain_skb is allocated and used exclusively in
ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is
processed and subsequently freed (in error paths) only during the next
call of ath9k_hif_usb_rx_stream().

So, if the urbs are deallocated between those two calls due to the device
deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream()
is not called next time and the allocated remain_skb is leaked. Our local
Syzkaller instance was able to trigger that.

remain_skb makes sense when receiving two consecutive urbs which are
logically linked together, i.e. a specific data field from the first skb
indicates a cached skb to be allocated, memcpy'd with some data and
subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs
deallocation supposedly makes that link irrelevant so we need to free the
cached skb in those cases.

Fix the leak by introducing a function to explicitly free remain_skb (if
it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL
when it has not been allocated at all (hif_dev struct is kzalloced) or
when it has been processed in next call to ath9k_hif_usb_rx_stream().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 08 Oct 2025 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Wed, 08 Oct 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Tue, 07 Oct 2025 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: wifi: ath9k: hif_usb: fix memory leak of remain_skbs hif_dev->remain_skb is allocated and used exclusively in ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is processed and subsequently freed (in error paths) only during the next call of ath9k_hif_usb_rx_stream(). So, if the urbs are deallocated between those two calls due to the device deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream() is not called next time and the allocated remain_skb is leaked. Our local Syzkaller instance was able to trigger that. remain_skb makes sense when receiving two consecutive urbs which are logically linked together, i.e. a specific data field from the first skb indicates a cached skb to be allocated, memcpy'd with some data and subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs deallocation supposedly makes that link irrelevant so we need to free the cached skb in those cases. Fix the leak by introducing a function to explicitly free remain_skb (if it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL when it has not been allocated at all (hif_dev struct is kzalloced) or when it has been processed in next call to ath9k_hif_usb_rx_stream(). Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Title wifi: ath9k: hif_usb: fix memory leak of remain_skbs
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-07T15:19:41.028Z

Reserved: 2025-10-07T15:16:59.658Z

Link: CVE-2023-53641

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-10-07T16:15:47.390

Modified: 2025-10-08T19:38:09.863

Link: CVE-2023-53641

cve-icon Redhat

Severity : Important

Publid Date: 2025-10-07T00:00:00Z

Links: CVE-2023-53641 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-10-08T13:36:27Z