CVE-2025-39997

CVE-2025-39997 is a security vulnerability that is still awaiting full analysis and scoring. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

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.

Frequently asked questions

What is CVE-2025-39997?
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.
Is CVE-2025-39997 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-39997?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-39997 have an EU (EUVD) identifier?
Yes. CVE-2025-39997 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34576.
When was CVE-2025-39997 published?
CVE-2025-39997 was published on 2025-10-15 and last updated on 2026-06-17.

References