CVE Catalog

CVE-2026-80829

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the ALSA: usb-audio driver has an out-of-bounds write vulnerability in snd_usbmidi_novation_output(). A malicious USB device can advertise wMaxPacketSize=1, leading to a negative transfer length and writing beyond the buffer. The fix adds a check that the endpoint can hold the header plus at least one payload byte.

Risk Assessment

The vulnerability could allow an attacker with USB port access to write beyond the allocated buffer, potentially causing a system crash or arbitrary code execution.

Recommendation

Update the Linux kernel to a version with the fix to prevent exploitation.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix OOB write in snd_usbmidi_novation_output() snd_usbmidi_novation_output() lays out a two-byte header at transfer_buffer[0..1] and passes &transfer_buffer[2] together with a length of ep->max_transfer - 2 to snd_rawmidi_transmit(): count = snd_rawmidi_transmit(ep->ports[0].substream, &transfer_buffer[2], ep->max_transfer - 2); ep->max_transfer comes from the output endpoint's wMaxPacketSize via usb_maxpacket(). A malformed or malicious device can advertise a bulk OUT endpoint with a wMaxPacketSize of 1 - the USB core only clamps this value downwards - so ep->max_transfer becomes 1 and the count argument becomes -1. snd_rawmidi_transmit() passes the negative count on to __snd_rawmidi_transmit_peek(), where "if (count1 > count) count1 = count" leaves count1 negative; get_aligned_size() keeps it negative for a byte-stream substream, so the following memcpy(buffer, ..., count1) runs with a (size_t)-1 length and writes far past the transfer buffer, which was allocated with usb_alloc_coherent(ep->max_transfer). This is the same class of bug that was fixed for snd_usbmidi_akai_output() in commit 0970274613fb ("ALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output()"); the novation output routine was left unguarded. Bail out when the endpoint cannot hold the two-byte header plus at least one payload byte.

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