CVE-2026-23198

Published Feb 14, 2026

Last updated 2 months ago

CVSS high 7.8

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: KVM: Don't clobber irqfd routing type when deassigning irqfd When deassigning a KVM_IRQFD, don't clobber the irqfd's copy of the IRQ's routing entry as doing so breaks kvm_arch_irq_bypass_del_producer() on x86 and arm64, which explicitly look for KVM_IRQ_ROUTING_MSI. Instead, to handle a concurrent routing update, verify that the irqfd is still active before consuming the routing information. As evidenced by the x86 and arm64 bugs, and another bug in kvm_arch_update_irqfd_routing() (see below), clobbering the entry type without notifying arch code is surprising and error prone. As a bonus, checking that the irqfd is active provides a convenient location for documenting _why_ KVM must not consume the routing entry for an irqfd that is in the process of being deassigned: once the irqfd is deleted from the list (which happens *before* the eventfd is detached), it will no longer receive updates via kvm_irq_routing_update(), and so KVM could deliver an event using stale routing information (relative to KVM_SET_GSI_ROUTING returning to userspace). As an even better bonus, explicitly checking for the irqfd being active fixes a similar bug to the one the clobbering is trying to prevent: if an irqfd is deactivated, and then its routing is changed, kvm_irq_routing_update() won't invoke kvm_arch_update_irqfd_routing() (because the irqfd isn't in the list). And so if the irqfd is in bypass mode, IRQs will continue to be posted using the old routing information. As for kvm_arch_irq_bypass_del_producer(), clobbering the routing type results in KVM incorrectly keeping the IRQ in bypass mode, which is especially problematic on AMD as KVM tracks IRQs that are being posted to a vCPU in a list whose lifetime is tied to the irqfd. Without the help of KASAN to detect use-after-free, the most common sympton on AMD is a NULL pointer deref in amd_iommu_update_ga() due to the memory for irqfd structure being re-allocated and zeroed, resulting in irqfd->irq_bypass_data being NULL when read by avic_update_iommu_vcpu_affinity(): BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 40cf2b9067 P4D 40cf2b9067 PUD 408362a067 PMD 0 Oops: Oops: 0000 [#1] SMP CPU: 6 UID: 0 PID: 40383 Comm: vfio_irq_test Tainted: G U W O 6.19.0-smp--5dddc257e6b2-irqfd #31 NONE Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025 RIP: 0010:amd_iommu_update_ga+0x19/0xe0 Call Trace: <TASK> avic_update_iommu_vcpu_affinity+0x3d/0x90 [kvm_amd] __avic_vcpu_load+0xf4/0x130 [kvm_amd] kvm_arch_vcpu_load+0x89/0x210 [kvm] vcpu_load+0x30/0x40 [kvm] kvm_arch_vcpu_ioctl_run+0x45/0x620 [kvm] kvm_vcpu_ioctl+0x571/0x6a0 [kvm] __se_sys_ioctl+0x6d/0xb0 do_syscall_64+0x6f/0x9d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x46893b </TASK> ---[ end trace 0000000000000000 ]--- If AVIC is inhibited when the irfd is deassigned, the bug will manifest as list corruption, e.g. on the next irqfd assignment. list_add corruption. next->prev should be prev (ffff8d474d5cd588), but was 0000000000000000. (next=ffff8d8658f86530). ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:31! Oops: invalid opcode: 0000 [#1] SMP CPU: 128 UID: 0 PID: 80818 Comm: vfio_irq_test Tainted: G U W O 6.19.0-smp--f19dc4d680ba-irqfd #28 NONE Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025 RIP: 0010:__list_add_valid_or_report+0x97/0xc0 Call Trace: <TASK> avic_pi_update_irte+0x28e/0x2b0 [kvm_amd] kvm_pi_update_irte+0xbf/0x190 [kvm] kvm_arch_irq_bypass_add_producer+0x72/0x90 [kvm] irq_bypass_register_consumer+0xcd/0x170 [irqbypa ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.•CVE-2026-46300
  2. In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec(). Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused.•CVE-2026-43500
  3. In the Linux kernel, the following vulnerability has been resolved: scsi: storvsc: Fix scheduling while atomic on PREEMPT_RT This resolves the follow splat and lock-up when running with PREEMPT_RT enabled on Hyper-V: [ 415.140818] BUG: scheduling while atomic: stress-ng-iomix/1048/0x00000002 [ 415.140822] INFO: lockdep is turned off. [ 415.140823] Modules linked in: intel_rapl_msr intel_rapl_common intel_uncore_frequency_common intel_pmc_core pmt_telemetry pmt_discovery pmt_class intel_pmc_ssram_telemetry intel_vsec ghash_clmulni_intel aesni_intel rapl binfmt_misc nls_ascii nls_cp437 vfat fat snd_pcm hyperv_drm snd_timer drm_client_lib drm_shmem_helper snd sg soundcore drm_kms_helper pcspkr hv_balloon hv_utils evdev joydev drm configfs efi_pstore nfnetlink vsock_loopback vmw_vsock_virtio_transport_common hv_sock vmw_vsock_vmci_transport vsock vmw_vmci efivarfs autofs4 ext4 crc16 mbcache jbd2 sr_mod sd_mod cdrom hv_storvsc serio_raw hid_generic scsi_transport_fc hid_hyperv scsi_mod hid hv_netvsc hyperv_keyboard scsi_common [ 415.140846] Preemption disabled at: [ 415.140847] [<ffffffffc0656171>] storvsc_queuecommand+0x2e1/0xbe0 [hv_storvsc] [ 415.140854] CPU: 8 UID: 0 PID: 1048 Comm: stress-ng-iomix Not tainted 6.19.0-rc7 #30 PREEMPT_{RT,(full)} [ 415.140856] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/04/2024 [ 415.140857] Call Trace: [ 415.140861] <TASK> [ 415.140861] ? storvsc_queuecommand+0x2e1/0xbe0 [hv_storvsc] [ 415.140863] dump_stack_lvl+0x91/0xb0 [ 415.140870] __schedule_bug+0x9c/0xc0 [ 415.140875] __schedule+0xdf6/0x1300 [ 415.140877] ? rtlock_slowlock_locked+0x56c/0x1980 [ 415.140879] ? rcu_is_watching+0x12/0x60 [ 415.140883] schedule_rtlock+0x21/0x40 [ 415.140885] rtlock_slowlock_locked+0x502/0x1980 [ 415.140891] rt_spin_lock+0x89/0x1e0 [ 415.140893] hv_ringbuffer_write+0x87/0x2a0 [ 415.140899] vmbus_sendpacket_mpb_desc+0xb6/0xe0 [ 415.140900] ? rcu_is_watching+0x12/0x60 [ 415.140902] storvsc_queuecommand+0x669/0xbe0 [hv_storvsc] [ 415.140904] ? HARDIRQ_verbose+0x10/0x10 [ 415.140908] ? __rq_qos_issue+0x28/0x40 [ 415.140911] scsi_queue_rq+0x760/0xd80 [scsi_mod] [ 415.140926] __blk_mq_issue_directly+0x4a/0xc0 [ 415.140928] blk_mq_issue_direct+0x87/0x2b0 [ 415.140931] blk_mq_dispatch_queue_requests+0x120/0x440 [ 415.140933] blk_mq_flush_plug_list+0x7a/0x1a0 [ 415.140935] __blk_flush_plug+0xf4/0x150 [ 415.140940] __submit_bio+0x2b2/0x5c0 [ 415.140944] ? submit_bio_noacct_nocheck+0x272/0x360 [ 415.140946] submit_bio_noacct_nocheck+0x272/0x360 [ 415.140951] ext4_read_bh_lock+0x3e/0x60 [ext4] [ 415.140995] ext4_block_write_begin+0x396/0x650 [ext4] [ 415.141018] ? __pfx_ext4_da_get_block_prep+0x10/0x10 [ext4] [ 415.141038] ext4_da_write_begin+0x1c4/0x350 [ext4] [ 415.141060] generic_perform_write+0x14e/0x2c0 [ 415.141065] ext4_buffered_write_iter+0x6b/0x120 [ext4] [ 415.141083] vfs_write+0x2ca/0x570 [ 415.141087] ksys_write+0x76/0xf0 [ 415.141089] do_syscall_64+0x99/0x1490 [ 415.141093] ? rcu_is_watching+0x12/0x60 [ 415.141095] ? finish_task_switch.isra.0+0xdf/0x3d0 [ 415.141097] ? rcu_is_watching+0x12/0x60 [ 415.141098] ? lock_release+0x1f0/0x2a0 [ 415.141100] ? rcu_is_watching+0x12/0x60 [ 415.141101] ? finish_task_switch.isra.0+0xe4/0x3d0 [ 415.141103] ? rcu_is_watching+0x12/0x60 [ 415.141104] ? __schedule+0xb34/0x1300 [ 415.141106] ? hrtimer_try_to_cancel+0x1d/0x170 [ 415.141109] ? do_nanosleep+0x8b/0x160 [ 415.141111] ? hrtimer_nanosleep+0x89/0x100 [ 415.141114] ? __pfx_hrtimer_wakeup+0x10/0x10 [ 415.141116] ? xfd_validate_state+0x26/0x90 [ 415.141118] ? rcu_is_watching+0x12/0x60 [ 415.141120] ? do_syscall_64+0x1e0/0x1490 [ 415.141121] ? do_syscall_64+0x1e0/0x1490 [ 415.141123] ? rcu_is_watching+0x12/0x60 [ 415.141124] ? do_syscall_64+0x1e0/0x1490 [ 415.141125] ? do_syscall_64+0x1e0/0x1490 [ 415.141127] ? irqentry_exit+0x140/0 ---truncated---•CVE-2026-43475
  4. In the Linux kernel, the following vulnerability has been resolved: fs: init flags_valid before calling vfs_fileattr_get syzbot reported a uninit-value bug in [1]. Similar to the "*get" context where the kernel's internal file_kattr structure is initialized before calling vfs_fileattr_get(), we should use the same mechanism when using fa. [1] BUG: KMSAN: uninit-value in fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517 fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517 vfs_fileattr_get fs/file_attr.c:94 [inline] __do_sys_file_getattr fs/file_attr.c:416 [inline] Local variable fa.i created at: __do_sys_file_getattr fs/file_attr.c:380 [inline] __se_sys_file_getattr+0x8c/0xbd0 fs/file_attr.c:372•CVE-2026-43474
  5. In the Linux kernel, the following vulnerability has been resolved: scsi: mpi3mr: Add NULL checks when resetting request and reply queues The driver encountered a crash during resource cleanup when the reply and request queues were NULL due to freed memory. This issue occurred when the creation of reply or request queues failed, and the driver freed the memory first, but attempted to mem set the content of the freed memory, leading to a system crash. Add NULL pointer checks for reply and request queues before accessing the reply/request memory during cleanup•CVE-2026-43473

References

Sources include official advisories and independent security research.