{"id":"CVE-2021-47390","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()\n\nKASAN reports the following issue:\n\n BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798\n\n CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---\n Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020\n Call Trace:\n  dump_stack+0xa5/0xe6\n  print_address_description.constprop.0+0x18/0x130\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  __kasan_report.cold+0x7f/0x114\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kasan_report+0x38/0x50\n  kasan_check_range+0xf5/0x1d0\n  kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]\n  ? kvm_arch_exit+0x110/0x110 [kvm]\n  ? sched_clock+0x5/0x10\n  ioapic_write_indirect+0x59f/0x9e0 [kvm]\n  ? static_obj+0xc0/0xc0\n  ? __lock_acquired+0x1d2/0x8c0\n  ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]\n\nThe problem appears to be that 'vcpu_bitmap' is allocated as a single long\non stack and it should really be KVM_MAX_VCPUS long. We also seem to clear\nthe lower 16 bits of it with bitmap_zero() for no particular reason (my\nguess would be that 'bitmap' and 'vcpu_bitmap' variables in\nkvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed\n16-bit long, the later should accommodate all possible vCPUs).","modified":"2026-03-14T14:59:09.313340Z","published":"2024-05-21T15:15:24.397Z","related":["SUSE-SU-2024:2008-1","SUSE-SU-2024:2011-1","SUSE-SU-2024:2019-1","SUSE-SU-2024:2189-1","SUSE-SU-2024:2190-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69"},{"type":"FIX","url":"https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792"},{"type":"FIX","url":"https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25b"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47390.json","unresolved_ranges":[{"events":[{"introduced":"5.5"},{"fixed":"5.10.71"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.14.10"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc2"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc3"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"}]}