CVE-2026-80973: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: 6fire: bound the MIDI event length from the device usb6fire_comm_receiver_handler() forwards a MIDI event using a length byte the device supplies, with no bound and no check that the transfer delivered that many bytes: if (!urb->status) { if (rt->receiver_buffer[0] == 0x10) /* midi in event */ if (midi_rt) midi_rt->in_received(midi_rt, rt->receiver_buffer + 2, rt->receiver_buffer[1]); } receiver_buffer is a 64-byte kzalloc() buffer (COMM_RECEIVER_BUFSIZE), so only 62 bytes follow the two-byte header. receiver_buffer[1] is a u8 the device chooses, so a device that answers with 0x10 and a length of 0xFF makes snd_rawmidi_receive() read 255 bytes starting two bytes into a 64-byte object. The bytes past the buffer are handed to userspace through the rawmidi read path. urb->actual_length is not consulted either, so a short transfer leaves both the type byte and the length byte at their previous values and the handler acts on stale data. The receiver URB is submitted from usb6fire_comm_init() at probe, so the read happens on plug with no user action; forwarding to userspace also needs a MIDI input substream open, since usb6fire_midi_in_received() only calls snd_rawmidi_receive() when rt->in is set. KASAN on 7.2.0-rc5 (arm64), single packet from an emulated device: BUG: KASAN: slab-out-of-bounds in snd_rawmidi_receive Read of size 255 at addr ffff000009f64682 by task bash/183 __asan_memcpy snd_rawmidi_receive usb6fire_midi_in_received [snd_usb_6fire] usb6fire_comm_receiver_handler [snd_usb_6fire] Allocated by task 11: usb6fire_comm_init [snd_usb_6fire] usb6fire_chip_probe [snd_usb_6fire] The buggy address is located 2 bytes inside of allocated 64-byte region [ffff000009f64680, ffff000009f646c0) Reject the event when the length exceeds the bytes that follow the header, and require the transfer to have delivered the header plus that many bytes. The receiver URB is submitted with a 64-byte transfer_buffer_length, so a genuine device cannot deliver an event longer than those 62 bytes and nothing valid is dropped. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

Metrics

EPSS Probability

0.20%

9.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < c9204bc2ed2010e2469dbe5fce598878a37efd04; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 2c590d5e1b1595d5c8fa0b72d2897423ce9985ca; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 0c8a3c773823cf12abd39c480aed70e25c384630; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 00e84a9ff2d43953ae261995cae94d46f4c307a6; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 466e911bbbbb779bb06337e35a286e5ca7af16b3; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 2a6f6fba3bd31d2e8c957fefa29156e35e5e75d5; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < 34816e2cfeabafb8eccf54687186ce25699e8363; >= c6d43ba816d1cf1d125bfbfc938f2a28a87facf9, < a478893b59e36cfe7d77a76b352f2db55502e879
Linux	Linux	2.6.39

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-80973?

In the Linux kernel, the following vulnerability has been resolved: ALSA: 6fire: bound the MIDI event length from the device usb6fire_comm_receiver_handler() forwards a MIDI event using a length byte the device supplies, with no bound and no check that the transfer delivered that many bytes: if (!urb->status) { if (rt->receiver_buffer[0] == 0x10) /* midi in event */ if (midi_rt) midi_rt->in_received(midi_rt, rt->receiver_buffer + 2, rt->receiver_buffer[1]); } receiver_buffer is a 64-byte kzalloc() buffer (COMM_RECEIVER_BUFSIZE), so only 62 bytes follow the two-byte header. receiver_buffer[1] is a u8 the device chooses, so a device that answers with 0x10 and a length of 0xFF makes snd_rawmidi_receive() read 255 bytes starting two bytes into a 64-byte object. The bytes past the buffer are handed to userspace through the rawmidi read path. urb->actual_length is not consulted either, so a short transfer leaves both the type byte and the length byte at their previous values and the handler acts on stale data. The receiver URB is submitted from usb6fire_comm_init() at probe, so the read happens on plug with no user action; forwarding to userspace also needs a MIDI input substream open, since usb6fire_midi_in_received() only calls snd_rawmidi_receive() when rt->in is set. KASAN on 7.2.0-rc5 (arm64), single packet from an emulated device: BUG: KASAN: slab-out-of-bounds in snd_rawmidi_receive Read of size 255 at addr ffff000009f64682 by task bash/183 __asan_memcpy snd_rawmidi_receive usb6fire_midi_in_received [snd_usb_6fire] usb6fire_comm_receiver_handler [snd_usb_6fire] Allocated by task 11: usb6fire_comm_init [snd_usb_6fire] usb6fire_chip_probe [snd_usb_6fire] The buggy address is located 2 bytes inside of allocated 64-byte region [ffff000009f64680, ffff000009f646c0) Reject the event when the length exceeds the bytes that follow the header, and require the transfer to have delivered the header plus that many bytes. The receiver URB is submitted with a 64-byte transfer_buffer_length, so a genuine device cannot deliver an event longer than those 62 bytes and nothing valid is dropped. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

How severe is CVE-2026-80973?

Severity scoring for CVE-2026-80973 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-80973?

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.

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