{"cve":"CVE-2026-93181","nvd":{"published":"2026-09-17T17:18:14.027","modified":"2026-10-21T13:21:02.227","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19","https://git.kernel.org/stable/c/3cfd351602e6704cce9bc766a974afb9f745d44b","https://git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-93181","score":0.00206,"percentile":0.10607,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}