{"id":"CVE-2026-99168","state":"PUBLISHED","title":"mshv_vtl: Check per-CPU register page before mmap","description":"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() 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.","publishedAt":"2026-10-28T10:35:19.539Z","updatedAt":"2026-10-28T10:35:19.539Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f","status":"affected","lessThan":"5c0757b065fbd140d8fbd05dc2c2146b713dfa68","versionType":"git"},{"version":"7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f","status":"affected","lessThan":"874194a8de75fc2f4d1fb70c670b289b7e48f93e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_vtl_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.19","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_vtl_main.c"]}],"references":["https://git.kernel.org/stable/c/5c0757b065fbd140d8fbd05dc2c2146b713dfa68","https://git.kernel.org/stable/c/874194a8de75fc2f4d1fb70c670b289b7e48f93e"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99168.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99168","state":"PUBLISHED","datePublished":"2026-10-28T10:35:19.539Z","dateUpdated":"2026-10-28T10:35:19.539Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.398Z"},"containers":{"cna":{"title":"mshv_vtl: Check per-CPU register page before mmap","descriptions":[{"lang":"en","value":"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() 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f","status":"affected","lessThan":"5c0757b065fbd140d8fbd05dc2c2146b713dfa68","versionType":"git"},{"version":"7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f","status":"affected","lessThan":"874194a8de75fc2f4d1fb70c670b289b7e48f93e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_vtl_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.19","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/mshv_vtl_main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5c0757b065fbd140d8fbd05dc2c2146b713dfa68"},{"url":"https://git.kernel.org/stable/c/874194a8de75fc2f4d1fb70c670b289b7e48f93e"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-28T10:35:19.539Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}