{"id":"CVE-2026-98713","title":"KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT\n\nFGUs don't actually require hardware support, so don't gate fgt trap\nconfig insertion on FGT. This is the on…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 2f4a15c52a552c5244ec27f4ca8bda855594f918","Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087","Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < af3300b3a6bace925a496f3520e171c07b999c72","Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07","Linux 6.9"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:46:45.902Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98713","references":[{"url":"https://git.kernel.org/stable/c/2f4a15c52a552c5244ec27f4ca8bda855594f918"},{"url":"https://git.kernel.org/stable/c/1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087"},{"url":"https://git.kernel.org/stable/c/af3300b3a6bace925a496f3520e171c07b999c72"},{"url":"https://git.kernel.org/stable/c/4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.512Z","slug":"CVE-2026-98713","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT\n\nFGUs don't actually require hardware support, so don't gate fgt trap\nconfig insertion on FGT. This is the only action required to allow FGUs\nalways, as kvm_calculate_traps() already computes the FGU bits with or\nwithout FEAT_FGT.\n\nThis also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1\nwithout FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the\ncourse-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(),\nwhich expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF\nwill be injected without needing the specific handler.\n\n[oliver: Take Wei-Lin's suggested changelog]\n\n## Affected\n\n- `Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 2f4a15c52a552c5244ec27f4ca8bda855594f918`\n- `Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087`\n- `Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < af3300b3a6bace925a496f3520e171c07b999c72`\n- `Linux >= f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f < 4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07`\n- `Linux 6.9`\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":[]}