CVE-2023-53641
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-07

Last updated on: 2026-02-03

Assigner: kernel.org

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.
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Meta Information
Published
2025-10-07
Last Modified
2026-02-03
Generated
2026-06-16
AI Q&A
2025-10-07
EPSS Evaluated
2026-06-15
NVD
CVE-2023-53641
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.3 (inc) to 6.3.2 (inc)
linux kernel *
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-401 The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
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Executive Summary

This vulnerability is a memory leak in the Linux kernel's ath9k wireless driver, specifically in the hif_usb component. The issue occurs because a buffer (remain_skb) allocated during USB receive operations is not always freed if the device is deinitialized or suspended before the next expected processing call. This can cause the allocated memory to be leaked, as the code assumes the buffer will be freed during the next call, which may never happen if the device state changes.

Impact Analysis

The memory leak can lead to increased memory usage over time, potentially causing system instability or crashes if the leaked memory accumulates. This can degrade the performance of the affected device or system running the vulnerable Linux kernel with the ath9k driver.

Mitigation Strategies

To mitigate this vulnerability, update the Linux kernel to a version where the memory leak in ath9k_hif_usb_rx_stream() has been fixed. This fix involves freeing the remain_skb explicitly when the rx urbs are deallocated, preventing memory leaks during device deinitialization or suspend. Until the update is applied, avoid frequent device deinitialization or suspend cycles that could trigger the leak.

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