{"cve":"CVE-2026-80829","nvd":{"published":"2026-09-04T16:18:10.997","modified":"2026-10-19T09:17:17.987","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: fix OOB write in snd_usbmidi_novation_output()\n\nsnd_usbmidi_novation_output() lays out a two-byte header at\ntransfer_buffer[0..1] and passes &transfer_buffer[2] together with a\nlength of ep->max_transfer - 2 to snd_rawmidi_transmit():\n\n\tcount = snd_rawmidi_transmit(ep->ports[0].substream,\n\t\t\t\t     &transfer_buffer[2],\n\t\t\t\t     ep->max_transfer - 2);\n\nep->max_transfer comes from the output endpoint's wMaxPacketSize via\nusb_maxpacket(). A malformed or malicious device can advertise a bulk\nOUT endpoint with a wMaxPacketSize of 1 - the USB core only clamps this\nvalue downwards - so ep->max_transfer becomes 1 and the count argument\nbecomes -1.\n\nsnd_rawmidi_transmit() passes the negative count on to\n__snd_rawmidi_transmit_peek(), where \"if (count1 > count) count1 = count\"\nleaves count1 negative; get_aligned_size() keeps it negative for a\nbyte-stream substream, so the following memcpy(buffer, ..., count1) runs\nwith a (size_t)-1 length and writes far past the transfer buffer, which\nwas allocated with usb_alloc_coherent(ep->max_transfer).\n\nThis is the same class of bug that was fixed for snd_usbmidi_akai_output()\nin commit 0970274613fb (\"ALSA: usb-audio: fix OOB write in\nsnd_usbmidi_akai_output()\"); the novation output routine was left\nunguarded. Bail out when the endpoint cannot hold the two-byte header\nplus at least one payload byte.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/1035a8f63bae28e498b0e7b5ac91d749844a7158","https://git.kernel.org/stable/c/1074c2306901b44ebcb83855583c6776e1e392ea","https://git.kernel.org/stable/c/558fc4485ecc704edfe7876d6cebae4738ff7ef8","https://git.kernel.org/stable/c/7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870","https://git.kernel.org/stable/c/7f00dbddb51f4f74325cdc7c3f6b19fb3392481a"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:03.409947763+00:00"},"epss":{"cve":"CVE-2026-80829","score":0.00195,"percentile":0.09116,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}