CVE-2025-40269
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-06

Last updated on: 2025-12-08

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix potential overflow of PCM transfer buffer The PCM stream data in USB-audio driver is transferred over USB URB packet buffers, and each packet size is determined dynamically. The packet sizes are limited by some factors such as wMaxPacketSize USB descriptor. OTOH, in the current code, the actually used packet sizes are determined only by the rate and the PPS, which may be bigger than the size limit above. This results in a buffer overflow, as reported by syzbot. Basically when the limit is smaller than the calculated packet size, it implies that something is wrong, most likely a weird USB descriptor. So the best option would be just to return an error at the parameter setup time before doing any further operations. This patch introduces such a sanity check, and returns -EINVAL when the packet size is greater than maxpacksize. The comparison with ep->packsize[1] alone should suffice since it's always equal or greater than ep->packsize[0].
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Meta Information
Published
2025-12-06
Last Modified
2025-12-08
Generated
2026-05-07
AI Q&A
2025-12-07
EPSS Evaluated
2026-05-05
NVD
CVE-2025-40269
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a potential buffer overflow in the Linux kernel's USB audio driver (ALSA). The issue arises because the size of PCM audio data packets transferred over USB is dynamically determined, but the code does not properly check if the packet size exceeds the maximum allowed size defined by the USB descriptor. When the calculated packet size is larger than the allowed maximum, it can cause a buffer overflow. The fix adds a sanity check to return an error if the packet size is too large, preventing the overflow.


How can this vulnerability impact me? :

This vulnerability can lead to a buffer overflow in the USB audio driver, which may cause system instability, crashes, or potentially allow an attacker to execute arbitrary code or escalate privileges on the affected system.


What immediate steps should I take to mitigate this vulnerability?

The vulnerability is fixed by a patch that adds a sanity check in the Linux kernel's USB-audio driver to prevent buffer overflow by returning an error when the packet size exceeds the maximum allowed size. To mitigate this vulnerability immediately, you should update your Linux kernel to a version that includes this fix.


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