{"id":"CVE-2026-43161","title":"iommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode\n\nPCIe endpoints with ATS enabled and passed through to userspace\n(e.g., QEMU, DPDK) …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < 48b3f08e68b29a79527869cdde7298ca2a9b9646","Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < e70d5feb10c5ba2bbf7ca400b8f39a2f82d653e8","Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < bc0490ad9edf5c6f98e39fbbee2877b85261a5ae","Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < 42662d19839f34735b718129ea200e3734b07e50","Linux 99301a53a1378f8863ac7850b9589f997bb0e125","Linux 948ec6d003280d49aca49b366aa5cb140f87434d","Linux >= 5.12.19 < 5.13","Linux >= 5.13.4 < 5.14","Linux 5.14"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T15:29:59.644276Z"},"published":"2026-05-06","updated":"2026-11-06","sourceUpdated":"2026-11-06T15:32:34.545Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-43161","references":[{"url":"https://git.kernel.org/stable/c/48b3f08e68b29a79527869cdde7298ca2a9b9646"},{"url":"https://git.kernel.org/stable/c/e70d5feb10c5ba2bbf7ca400b8f39a2f82d653e8"},{"url":"https://git.kernel.org/stable/c/bc0490ad9edf5c6f98e39fbbee2877b85261a5ae"},{"url":"https://git.kernel.org/stable/c/42662d19839f34735b718129ea200e3734b07e50"}],"tags":["cve.org"],"epss":0.00122,"epssPercentile":0.01988,"ingestedAt":"2026-11-06T15:54:04.022Z","slug":"CVE-2026-43161","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode\n\nPCIe endpoints with ATS enabled and passed through to userspace\n(e.g., QEMU, DPDK) can hard-lock the host when their link drops,\neither by surprise removal or by a link fault.\n\nCommit 4fc82cd907ac (\"iommu/vt-d: Don't issue ATS Invalidation\nrequest when device is disconnected\") adds pci_dev_is_disconnected()\nto devtlb_invalidation_with_pasid() so ATS invalidation is skipped\nonly when the device is being safely removed, but it applies only\nwhen Intel IOMMU scalable mode is enabled.\n\nWith scalable mode disabled or unsupported, a system hard-lock\noccurs when a PCIe endpoint's link drops because the Intel IOMMU\nwaits indefinitely for an ATS invalidation that cannot complete.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n domain_context_clear_one_cb\n pci_for_each_dma_alias\n device_block_translation\n blocking_domain_attach_dev\n iommu_deinit_device\n __iommu_group_remove_device\n iommu_release_device\n iommu_bus_notifier\n blocking_notifier_call_chain\n bus_notify\n device_del\n pci_remove_bus_device\n pci_stop_and_remove_bus_device\n pciehp_unconfigure_device\n pciehp_disable_slot\n pciehp_handle_presence_or_link_change\n pciehp_ist\n\nCommit 81e921fd3216 (\"iommu/vt-d: Fix NULL domain on device release\")\nadds intel_pasid_teardown_sm_context() to intel_iommu_release_device(),\nwhich calls qi_flush_dev_iotlb() and can also hard-lock the system\nwhen a PCIe endpoint's link drops.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n intel_context_flush_no_pasid\n device_pasid_table_teardown\n pci_pasid_table_teardown\n pci_for_each_dma_alias\n intel_pasid_teardown_sm_context\n intel_iommu_release_device\n iommu_deinit_device\n __iommu_group_remove_device\n iommu_release_device\n iommu_bus_notifier\n blocking_notifier_call_chain\n bus_notify\n device_del\n pci_remove_bus_device\n pci_stop_and_remove_bus_device\n pciehp_unconfigure_device\n pciehp_disable_slot\n pciehp_handle_presence_or_link_change\n pciehp_ist\n\nSometimes the endpoint loses connection without a link-down event\n(e.g., due to a link fault); killing the process (virsh destroy)\nthen hard-locks the host.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n domain_context_clear_one_cb\n pci_for_each_dma_alias\n device_block_translation\n blocking_domain_attach_dev\n __iommu_attach_device\n __iommu_device_set_domain\n __iommu_group_set_domain_internal\n iommu_detach_group\n vfio_iommu_type1_detach_group\n vfio_group_detach_container\n vfio_group_fops_release\n __fput\n\npci_dev_is_disconnected() only covers safe-removal paths;\npci_device_is_present() tests accessibility by reading\nvendor/device IDs and internally calls pci_dev_is_disconnected().\nOn a ConnectX-5 (8 GT/s, x2) this costs ~70 µs.\n\nSince __context_flush_dev_iotlb() is only called on\n{attach,release}_dev paths (not hot), add pci_device_is_present()\nthere to skip inaccessible devices and avoid the hard-lock.\n\n## Affected\n\n- `Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < 48b3f08e68b29a79527869cdde7298ca2a9b9646`\n- `Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < e70d5feb10c5ba2bbf7ca400b8f39a2f82d653e8`\n- `Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < bc0490ad9edf5c6f98e39fbbee2877b85261a5ae`\n- `Linux >= 37764b952e1b39053defc7ebe5dcd8c4e3e78de9 < 42662d19839f34735b718129ea200e3734b07e50`\n- `Linux 99301a53a1378f8863ac7850b9589f997bb0e125`\n- `Linux 948ec6d003280d49aca49b366aa5cb140f87434d`\n- `Linux >= 5.12.19 < 5.13`\n- `Linux >= 5.13.4 < 5.14`\n- `Linux 5.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}