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