{"cve":"CVE-2026-74636","nvd":{"published":"2026-08-22T16:16:36.750","modified":"2026-10-14T13:10:00.187","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix race between update_event_fields and, event_define_fields\n\nThe following sequence may leads race between event_define_fields()\nand update_event_fields():\n\n CPU0 (loads module A)                      CPU1 (loads module B)\n ===============================            ===============================\n load_module(A)                             load_module(B)\n   notifier_call_chain                        notifier_call_chain\n     trace_module_notify                        trace_module_notify\n       mutex_lock(&event_mutex)                   trace_event_update_all()\n         trace_module_add_events(A)                 down_write(&trace_event_sem)\n            __register_event(call_A)\n              __add_event_to_tracers(call_A)\n                event_define_fields(call_A)\n                  for each f:                         list_for_each_entry(field,\n                    list_add(&f->link,                                    &class->fields, link)\n                             &class->fields)            field = class->fields->next;\n\nWhere access to the class->fields is not protected by the event_mutex in\ntrace_event_update_all().\n\nThis produces the following panic:\n   Unable to handle kernel access ... at virtual address 0000000000000018\n   pc : update_event_fields+0xf8/0x368\n   Call trace:\n    update_event_fields+0xf8/0x368\n    trace_event_update_all+0x7c/0x2b4\n    trace_module_notify+0x4c/0x1dc\n    notifier_call_chain+0x84/0x168\n    blocking_notifier_call_chain_robust+0x64/0xd4\n    load_module+0x10c8/0x123c\n    __arm64_sys_finit_module+0x230/0x31c\n\nFix by taking event_mutex in trace_event_update_all() before\ntrace_event_sem.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5","https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555","https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c","https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8","https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-74636","score":0.00173,"percentile":0.06615,"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."]}