{"id":"CVE-2026-89929","published":"2026-09-16T11:17:02.180","lastModified":"2026-09-17T10:17:04.940","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nVM: Ensure INVVPID is emulated on the correct physical CPU\n\nWhen emulating INVVPID, KVM executes INVVPID on the physical CPU using\nvpid02 (instead of the L1 assigned VPID), after doing some validations\non the operands. However, it is possible that the physical CPU KVM\nexecutes INVVPID on is different from the CPU L2 is running on.\n\nFor example, in the following scenario:\n- L2 runs on CPU #1 and exits to L1 (vmx->nested.vmcs02.cpu=1)\n- L1 migrates to CPU #2 and executes INVVPID\n- KVM executes INVVPID on CPU #2\n- L1 migrates back to CPU #1 and runs L2 (vmx->nested.vmcs02.cpu=1)\n\nThe TLB entries on CPU #1 are never invalidated, because INVVPID was\nexecuted on CPU #2, and vmcs02 never ran on a different pCPU (i.e.\nvmx_vcpu_load_vmcs() will *not* request KVM_REQ_TLB_FLUSH).\n\nEnsure that INVVPID is being executed on the same pCPU that L2 last ran\non, and if not, fallback to clearing last_vpid=0 to trigger a full VPID\nflush on the next nested VM-Enter (as KVM will detect L1 using a\ndifferent VPID for L2). If L2 ends up running on a different pCPU, KVM\nwill flush the TLB anyway through vmx_vcpu_load_vmcs().","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/27bdeb5fd19046ffba9ff234e92fe553eb2efb30","tags":[]},{"url":"https://git.kernel.org/stable/c/6d00e67326d831e6e610933a3800712f4ffe6ec1","tags":[]},{"url":"https://git.kernel.org/stable/c/9941850e8adf164d005dbd3774c4b79e91a3cb8e","tags":[]},{"url":"https://git.kernel.org/stable/c/d03e721801ac54b9fdf05668aa0c069f07913b68","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"The flaw allows INVVPID to be emulated on a different physical CPU than the one L2 is running on, leading to potential TLB entry invalidation issues.","exploitability":"Exploitation requires precise control over CPU migration and timing, making it moderately difficult.","blast_radius":"If exploited, it could lead to unauthorized access or execution on the target system.","remediation":"Upgrade to the fixed version 5.10.135 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["kernel","vulnerability","cpu-migration","tlb-flush"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-30T09:14:46.186Z"}}