CVE Catalog

CVE-2026-90024

Unknown
Published: Translated: NVD NIST

Summary

A null-pointer dereference vulnerability exists in the Linux kernel's USB gadget MIDI 2.0 function, specifically in f_midi2_free_ep_reqs(). When configuring a MIDI 2.0 gadget via configfs with block direction set to SNDRV_UMP_DIR_INPUT, the midi1_ep_out endpoint is not initialized, leaving usb_ep->card as NULL. When the host later sets the alternate setting, f_midi2_free_ep_reqs() is called for the uninitialized endpoint, causing a kernel crash.

Risk Assessment

The vulnerability can cause a kernel oops and denial of service (DoS) on systems using the USB MIDI 2.0 gadget. Exploitation requires local gadget configuration via configfs and USB host interaction, which limits the attack surface.

Recommendation

Update the Linux kernel to a version containing the fix that replaces usb_ep->card->info.num_reqs with usb_ep->num_reqs in f_midi2_free_ep_reqs() and f_midi2_alloc_ep_reqs(). Until patched, avoid configuring the MIDI 2.0 gadget with SNDRV_UMP_DIR_INPUT direction.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: midi2: Fix null-pointer dereference in f_midi2_free_ep_reqs A null-pointer dereference occurs in f_midi2_free_ep_reqs() when attempting to clean up an endpoint that was never initialized. When configuring the MIDI 2.0 gadget via configfs and setting the block direction to SNDRV_UMP_DIR_INPUT, the initialization of the midi1_ep_out endpoint is explicitly skipped during the gadget bind phase (f_midi2_bind()). As a result, the usb_ep->card field remains NULL. Later, when the host sets the alternate setting, f_midi2_set_alt() unconditionally stops both the IN and OUT endpoints by calling f_midi2_stop_eps(), which in turn calls f_midi2_free_ep_reqs() for both endpoints. When f_midi2_free_ep_reqs() is called for the uninitialized midi1_ep_out, it attempts to dereference usb_ep->card to determine the number of requests to free, leading to a crash. Fix this by using usb_ep->num_reqs instead of usb_ep->card->info.num_reqs in f_midi2_free_ep_reqs(). usb_ep->num_reqs is correctly set during f_midi2_init_ep() and remains 0 if the endpoint was never initialized, safely avoiding the loop. For consistency, apply the same change to f_midi2_alloc_ep_reqs(). Oops: general protection fault, probably for non-canonical address 0xdffffc00000000ee: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000770-0x0000000000000777] ... RIP: 0010:f_midi2_free_ep_reqs drivers/usb/gadget/function/f_midi2.c:1166 [inline] RIP: 0010:f_midi2_stop_eps+0x28e/0x4d0 drivers/usb/gadget/function/f_midi2.c:1246 ... Call Trace: <TASK> f_midi2_set_alt+0x11c/0xf00 drivers/usb/gadget/function/f_midi2.c:1296 composite_setup+0x1ffd/0x3480 drivers/usb/gadget/composite.c:1933 configfs_composite_setup+0xbd/0x100 drivers/usb/gadget/configfs.c:1877

Vulnerability data from NVD (NIST) · CISA KEV · EPSS