{"id":"AZL-100458","summary":"CVE-2026-80973 affecting package kernel 6.6.150.1-1","details":"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-\u003estatus) {\n\t\tif (rt-\u003ereceiver_buffer[0] == 0x10) /* midi in event */\n\t\t\tif (midi_rt)\n\t\t\t\tmidi_rt-\u003ein_received(midi_rt,\n\t\t\t\t\t\trt-\u003ereceiver_buffer + 2,\n\t\t\t\t\t\trt-\u003ereceiver_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-\u003eactual_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-\u003ein 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 \u003cbaul.lee@xbow.com\u003e","modified":"2026-09-13T06:06:36Z","published":"2026-09-11T20:19:03Z","upstream":["CVE-2026-80973"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80973"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100458.json"}}],"schema_version":"1.9.0"}