CVE-2025-40275: In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix NULL pointer dereference in snd_usb_mixer_controls_badd In ...

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix NULL pointer dereference in snd_usb_mixer_controls_badd In snd_usb_create_streams(), for UAC version 3 devices, the Interface Association Descriptor (IAD) is retrieved via usb_ifnum_to_if(). If this call fails, a fallback routine attempts to obtain the IAD from the next interface and sets a BADD profile. However, snd_usb_mixer_controls_badd() assumes that the IAD retrieved from usb_ifnum_to_if() is always valid, without performing a NULL check. This can lead to a NULL pointer dereference when usb_ifnum_to_if() fails to find the interface descriptor. This patch adds a NULL pointer check after calling usb_ifnum_to_if() in snd_usb_mixer_controls_badd() to prevent the dereference. This issue was discovered by syzkaller, which triggered the bug by sending a crafted USB device descriptor.

Metrics

EPSS Probability

0.17%

6.0th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Dec 6, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40275?

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix NULL pointer dereference in snd_usb_mixer_controls_badd In snd_usb_create_streams(), for UAC version 3 devices, the Interface Association Descriptor (IAD) is retrieved via usb_ifnum_to_if(). If this call fails, a fallback routine attempts to obtain the IAD from the next interface and sets a BADD profile. However, snd_usb_mixer_controls_badd() assumes that the IAD retrieved from usb_ifnum_to_if() is always valid, without performing a NULL check. This can lead to a NULL pointer dereference when usb_ifnum_to_if() fails to find the interface descriptor. This patch adds a NULL pointer check after calling usb_ifnum_to_if() in snd_usb_mixer_controls_badd() to prevent the dereference. This issue was discovered by syzkaller, which triggered the bug by sending a crafted USB device descriptor.

How severe is CVE-2025-40275?

Severity scoring for CVE-2025-40275 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40275?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.