{"id":"CVE-2026-99168","title":"mshv_vtl: Check per-CPU register page before mmap","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nmshv_vtl: Check per-CPU register page before mmap\n\nRegister-page setup is optional for each CPU. If allocation or\nregistration fails, mshv_vtl_configure_reg_page() warn…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f < 5c0757b065fbd140d8fbd05dc2c2146b713dfa68","Linux >= 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f < 874194a8de75fc2f4d1fb70c670b289b7e48f93e","Linux 6.19"],"published":"2026-10-28","updated":"2026-10-28","sourceUpdated":"2026-10-28T10:35:19.539Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99168","references":[{"url":"https://git.kernel.org/stable/c/5c0757b065fbd140d8fbd05dc2c2146b713dfa68"},{"url":"https://git.kernel.org/stable/c/874194a8de75fc2f4d1fb70c670b289b7e48f93e"}],"tags":["cve.org"],"ingestedAt":"2026-10-28T11:09:40.390Z","slug":"CVE-2026-99168","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nmshv_vtl: Check per-CPU register page before mmap\n\nRegister-page setup is optional for each CPU. If allocation or\nregistration fails, mshv_vtl_configure_reg_page() warns and leaves that\nCPU's reg_page NULL, but initial context setup continues successfully.\nMeanwhile, successful setup on another CPU sets the global\nmshv_has_reg_page flag.\n\nmshv_vtl_fault() checks this global flag before selecting the requested\nCPU's register page. With mixed setup results across online CPUs, the\ncheck passes even for a CPU with no register page, reaching\nget_page(NULL) when userspace faults in that mapping.\n\nCheck the selected per-CPU register page before taking its reference and\nreturn VM_FAULT_SIGBUS if it is absent.\n\n## Affected\n\n- `Linux >= 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f < 5c0757b065fbd140d8fbd05dc2c2146b713dfa68`\n- `Linux >= 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f < 874194a8de75fc2f4d1fb70c670b289b7e48f93e`\n- `Linux 6.19`\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":[]}