{"id":"AZL-93878","summary":"CVE-2026-64364 affecting package kernel for versions less than 6.6.145.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nHID: multitouch: fix out-of-bounds bit access on mt_io_flags\n\nmt_io_flags is a single unsigned long, but mt_process_slot(),\nmt_release_pending_palms() and mt_release_contacts() use it as a\nper-slot bitmap indexed by the slot number. That slot number is only\nbounded by td-\u003emaxcontacts, which is taken from the device's\nContactCountMaximum feature report and can be up to 255, not by\nBITS_PER_LONG.\n\nAs a result, a multitouch device that advertises a large contact count\nmakes set_bit()/clear_bit() operate past the mt_io_flags word and\ncorrupt the adjacent members of struct mt_device. The sticky-fingers\nrelease timer is the easiest way to reach this. mt_release_contacts()\nruns\n\n\tfor (i = 0; i \u003c mt-\u003enum_slots; i++)\n\t\tclear_bit(i, &td-\u003emt_io_flags);\n\nwith num_slots == maxcontacts. For maxcontacts around 250 the loop\nclears the bits that overlap td-\u003eapplications.next, zeroing that list\nhead, and the list_for_each_entry() that immediately follows then\ndereferences NULL. The kernel panics from timer (softirq) context. On a\nKASAN build this shows up as a general protection fault in\nmt_release_contacts() with a null-ptr-deref at offset 0x58, which is\noffsetof(struct mt_application, num_received).\n\nThe state is reachable from an untrusted USB or Bluetooth HID\nmultitouch device; no local privileges are required.\n\nStore the per-slot active state in a separately allocated bitmap sized\nfor maxcontacts, the same pattern already used for pending_palm_slots,\nand keep only MT_IO_FLAGS_RUNNING in mt_io_flags. The two\n\"mt_io_flags & MT_IO_SLOTS_MASK\" arming checks become\nbitmap_empty(td-\u003eactive_slots, td-\u003emaxcontacts).\n\nMove MT_IO_FLAGS_RUNNING back to bit 0. It was bumped to bit 32 by the\nsame commit to leave the low byte for the slot bits; with the slot bits\ngone it fits in bit 0 again, which also keeps it within the unsigned\nlong on 32-bit.","modified":"2026-08-28T17:47:36.376164775Z","published":"2026-07-25T10:17:19Z","upstream":["CVE-2026-64364"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64364"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.145.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-93878.json"}}],"schema_version":"1.9.0"}