CVE-2025-39997
ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free The previous commit 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at removal") patched a UAF issue caused by the error timer. However, because the error timer kill added in this patch occurs after the endpoint delete, a race condition to UAF still occurs, albeit rarely. Additionally, since kill-cleanup for urb is also missing, freed memory can be accessed in interrupt context related to urb, which can cause UAF. Therefore, to prevent this, error timer and urb must be killed before freeing the heap memory.
INFO
Published Date :
Oct. 15, 2025, 8:15 a.m.
Last Modified :
Oct. 16, 2025, 3:28 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Kill error timer and urb before freeing heap memory.
- Apply kernel updates to resolve the race condition.
- Ensure proper cleanup of timers and URBs.
References to Advisories, Solutions, and Tools
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CVE-2025-39997.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-39997 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-39997
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 15, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free The previous commit 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at removal") patched a UAF issue caused by the error timer. However, because the error timer kill added in this patch occurs after the endpoint delete, a race condition to UAF still occurs, albeit rarely. Additionally, since kill-cleanup for urb is also missing, freed memory can be accessed in interrupt context related to urb, which can cause UAF. Therefore, to prevent this, error timer and urb must be killed before freeing the heap memory. Added Reference https://git.kernel.org/stable/c/353d8c715cc951a980728133c9dd64ca5a0a186c Added Reference https://git.kernel.org/stable/c/647d6b8d22be12842fde6ed0c56859ebc615f21e Added Reference https://git.kernel.org/stable/c/9f2c0ac1423d5f267e7f1d1940780fc764b0fee3 Added Reference https://git.kernel.org/stable/c/af600e7f5526d16146b3ae99f6ad57bfea79ca33 Added Reference https://git.kernel.org/stable/c/dc4874366cf6cf4a31d8fa4b7f0e2a5b2d7647ba