{"cve":"CVE-2026-80973","nvd":{"published":"2026-09-11T20:19:03.490","modified":"2026-10-19T09:17:29.270","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: 6fire: bound the MIDI event length from the device\n\nusb6fire_comm_receiver_handler() forwards a MIDI event using a length\nbyte the device supplies, with no bound and no check that the transfer\ndelivered that many bytes:\n\n\tif (!urb->status) {\n\t\tif (rt->receiver_buffer[0] == 0x10) /* midi in event */\n\t\t\tif (midi_rt)\n\t\t\t\tmidi_rt->in_received(midi_rt,\n\t\t\t\t\t\trt->receiver_buffer + 2,\n\t\t\t\t\t\trt->receiver_buffer[1]);\n\t}\n\nreceiver_buffer is a 64-byte kzalloc() buffer (COMM_RECEIVER_BUFSIZE), so\nonly 62 bytes follow the two-byte header.  receiver_buffer[1] is a u8 the\ndevice chooses, so a device that answers with 0x10 and a length of 0xFF\nmakes snd_rawmidi_receive() read 255 bytes starting two bytes into a\n64-byte object.  The bytes past the buffer are handed to userspace\nthrough the rawmidi read path.\n\nurb->actual_length is not consulted either, so a short transfer leaves\nboth the type byte and the length byte at their previous values and the\nhandler acts on stale data.\n\nThe receiver URB is submitted from usb6fire_comm_init() at probe, so the\nread happens on plug with no user action; forwarding to userspace also\nneeds a MIDI input substream open, since usb6fire_midi_in_received()\nonly calls snd_rawmidi_receive() when rt->in is set.\n\nKASAN on 7.2.0-rc5 (arm64), single packet from an emulated device:\n\n  BUG: KASAN: slab-out-of-bounds in snd_rawmidi_receive\n  Read of size 255 at addr ffff000009f64682 by task bash/183\n   __asan_memcpy\n   snd_rawmidi_receive\n   usb6fire_midi_in_received [snd_usb_6fire]\n   usb6fire_comm_receiver_handler [snd_usb_6fire]\n  Allocated by task 11:\n   usb6fire_comm_init [snd_usb_6fire]\n   usb6fire_chip_probe [snd_usb_6fire]\n  The buggy address is located 2 bytes inside of\n   allocated 64-byte region [ffff000009f64680, ffff000009f646c0)\n\nReject the event when the length exceeds the bytes that follow the\nheader, and require the transfer to have delivered the header plus that\nmany bytes.  The receiver URB is submitted with a 64-byte\ntransfer_buffer_length, so a genuine device cannot deliver an event\nlonger than those 62 bytes and nothing valid is dropped.\n\nDiscovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/00e84a9ff2d43953ae261995cae94d46f4c307a6","https://git.kernel.org/stable/c/0c8a3c773823cf12abd39c480aed70e25c384630","https://git.kernel.org/stable/c/2a6f6fba3bd31d2e8c957fefa29156e35e5e75d5","https://git.kernel.org/stable/c/2c590d5e1b1595d5c8fa0b72d2897423ce9985ca","https://git.kernel.org/stable/c/34816e2cfeabafb8eccf54687186ce25699e8363"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-80973","score":0.00216,"percentile":0.11962,"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."]}