{"id":"CVE-2026-46076","title":"KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1\n\nExplicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want\nto intercept VMMCALL, neste…","severity":"high","cvss":7.9,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 924d721fae95687acedbaf624a094ed0e8b67104","Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 009c0f726abeaa67aad1d96b883bdce01d405ce2","Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 5fb4a5f361565f5b629d8a8fe5288ce8463c5727","Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < c36991c6f8d2ab56ee67aff04e3c357f45cfc76c","Linux 6.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T15:19:27.445501Z"},"published":"2026-05-27","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:50.172Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-46076","references":[{"url":"https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104"},{"url":"https://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2"},{"url":"https://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727"},{"url":"https://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c"}],"tags":["cve.org"],"epss":0.00121,"epssPercentile":0.01761,"ingestedAt":"2026-10-16T17:24:46.705Z","slug":"CVE-2026-46076","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1\n\nExplicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want\nto intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the\nhypercall is something other than one of the supported Hyper-V hypercalls.\nWhen all of the above conditions are met, KVM will intercept VMMCALL but\nnever forward it to L1, i.e. will let L2 make hypercalls as if it were L1.\n\nThe TLFS says a whole lot of nothing about this scenario, so go with the\narchitectural behavior, which says that VMMCALL #UDs if it's not\nintercepted.\n\nOpportunistically do a 2-for-1 stub trade by stub-ifying the new API\ninstead of the helpers it uses.  The last remaining \"single\" stub will\nsoon be dropped as well.\n\n[sean: rewrite changelog and comment, tag for stable, remove defunct stubs]\n\n## Affected\n\n- `Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 924d721fae95687acedbaf624a094ed0e8b67104`\n- `Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 009c0f726abeaa67aad1d96b883bdce01d405ce2`\n- `Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < 5fb4a5f361565f5b629d8a8fe5288ce8463c5727`\n- `Linux >= 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 < c36991c6f8d2ab56ee67aff04e3c357f45cfc76c`\n- `Linux 6.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":43.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}