{"api_version":"1","generated_at":"2026-09-19T15:00:34+00:00","cve":"CVE-2026-93181","urls":{"html":"https://cve.report/CVE-2026-93181","api":"https://cve.report/api/cve/CVE-2026-93181.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-93181","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-93181"},"summary":{"title":"perf/x86/intel/uncore: Fix uncore_box ref/unref ordering","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix uncore_box ref/unref ordering\n\nIn uncore_event_cpu_online(), uncore_box_ref() was called before\nuncore_change_context().  uncore_box_ref() gates on box->cpu >= 0,\nbut box->cpu is still -1 at that point because uncore_change_context()\nhas not run yet.  As a result, the box is never initialized on the\nfirst CPU to come online in a die, leaving it permanently\nuninitialized in the single-CPU-per-die case.\n\nThus, box->refcnt is one count below the true value, and in the CPU\noffline path, the box will be torn down on the second-to-last CPU.\n\nIn uncore_event_cpu_offline(), uncore_box_unref() was called after\nuncore_change_context(), so box->cpu is already -1 when the collector\nCPU goes offline, which prevents it from tearing down the box.\n\nFix by swapping the call order in both paths so that\nuncore_box_{ref,unref}() runs at the point where box->cpu reflects\nthe correct context.\n\nMove allocate_boxes() out of uncore_box_ref() to enable this\nreordering.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:18:14","updated_at":"2026-09-17 17:18:14"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19","name":"https://git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375","name":"https://git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-93181","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93181","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c74443d92f68f07c03ae242ced554b749e6c6736 64aa1bb4017d598828c6d8cd718f43daf2a83375 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c74443d92f68f07c03ae242ced554b749e6c6736 174f0582e38abe03b88e15f04bfe58490f88cb19 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.11","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.6 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"93181","cve":"CVE-2026-93181","epss":"0.001890000","percentile":"0.088300000","score_date":"2026-09-18","updated_at":"2026-09-19 00:06:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["arch/x86/events/intel/uncore.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"64aa1bb4017d598828c6d8cd718f43daf2a83375","status":"affected","version":"c74443d92f68f07c03ae242ced554b749e6c6736","versionType":"git"},{"lessThan":"174f0582e38abe03b88e15f04bfe58490f88cb19","status":"affected","version":"c74443d92f68f07c03ae242ced554b749e6c6736","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["arch/x86/events/intel/uncore.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.11"},{"lessThan":"6.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.6","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix uncore_box ref/unref ordering\n\nIn uncore_event_cpu_online(), uncore_box_ref() was called before\nuncore_change_context().  uncore_box_ref() gates on box->cpu >= 0,\nbut box->cpu is still -1 at that point because uncore_change_context()\nhas not run yet.  As a result, the box is never initialized on the\nfirst CPU to come online in a die, leaving it permanently\nuninitialized in the single-CPU-per-die case.\n\nThus, box->refcnt is one count below the true value, and in the CPU\noffline path, the box will be torn down on the second-to-last CPU.\n\nIn uncore_event_cpu_offline(), uncore_box_unref() was called after\nuncore_change_context(), so box->cpu is already -1 when the collector\nCPU goes offline, which prevents it from tearing down the box.\n\nFix by swapping the call order in both paths so that\nuncore_box_{ref,unref}() runs at the point where box->cpu reflects\nthe correct context.\n\nMove allocate_boxes() out of uncore_box_ref() to enable this\nreordering."}],"providerMetadata":{"dateUpdated":"2026-09-17T16:12:08.716Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375"},{"url":"https://git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19"}],"title":"perf/x86/intel/uncore: Fix uncore_box ref/unref ordering","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-93181","datePublished":"2026-09-17T16:12:08.716Z","dateReserved":"2026-09-17T16:02:15.091Z","dateUpdated":"2026-09-17T16:12:08.716Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:18:14","lastModifiedDate":"2026-09-17 17:18:14","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"93181","Ordinal":"1","Title":"perf/x86/intel/uncore: Fix uncore_box ref/unref ordering","CVE":"CVE-2026-93181","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"93181","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix uncore_box ref/unref ordering\n\nIn uncore_event_cpu_online(), uncore_box_ref() was called before\nuncore_change_context().  uncore_box_ref() gates on box->cpu >= 0,\nbut box->cpu is still -1 at that point because uncore_change_context()\nhas not run yet.  As a result, the box is never initialized on the\nfirst CPU to come online in a die, leaving it permanently\nuninitialized in the single-CPU-per-die case.\n\nThus, box->refcnt is one count below the true value, and in the CPU\noffline path, the box will be torn down on the second-to-last CPU.\n\nIn uncore_event_cpu_offline(), uncore_box_unref() was called after\nuncore_change_context(), so box->cpu is already -1 when the collector\nCPU goes offline, which prevents it from tearing down the box.\n\nFix by swapping the call order in both paths so that\nuncore_box_{ref,unref}() runs at the point where box->cpu reflects\nthe correct context.\n\nMove allocate_boxes() out of uncore_box_ref() to enable this\nreordering.","Type":"Description","Title":"perf/x86/intel/uncore: Fix uncore_box ref/unref ordering"}]}}}