{"id":"CVE-2026-99163","aliases":[],"title":"tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"1f36e4ddd05d540f363dbaa4c23042549f15b3ef","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"deb336ae7c7b341591a6862cf6fcfeca97c77dfd","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"a244c241593b5b38a08f0df2cb43c26574efbdcb","versionType":"git"},{"version":"b9453380c1c542fd095a4dbe9251eeba4022bbce","status":"affected","versionType":"git"},{"version":"5f52389bdd9eafb63b3a2f804e02aeb17b6a5f55","status":"affected","versionType":"git"},{"version":"f3baa42afeea0d5f04ad31525e861199d02210cc","status":"affected","versionType":"git"},{"version":"5.10.237","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.15.124","status":"affected","lessThan":"5.16","versionType":"semver"},{"version":"6.1.43","status":"affected","lessThan":"6.2","versionType":"semver"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99163"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99163"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields\n\nIn check_synth_field(), when a synthetic event field is a stacktrace\n(field->is_stack) and the histogram field is not a \"long[\" stacktrace\narray, validation falls through to the generic size and signedness\ncomparison.\n\nBecause parse_synth_field() sets a stacktrace field's type to\n\"__data_loc unsigned long[]\", its size is sizeof(u64) and\nsynth_field_signed() marks it as signed.  Consequently, any 8-byte\nsigned scalar histogram field passes the fallback check, and its scalar\nvalue is subsequently dereferenced as a kernel stacktrace pointer in\nget_field_size() and trace_stack().\n\nFurthermore, checking strstr(hist_field->type, \"long[\") is insufficient\nbecause tracepoint fields defined with __bitmask() or __rel_bitmask()\nalso have type \"__data_loc unsigned long[]\" or \"__rel_loc unsigned\nlong[]\", whilst create_hist_field() treats them as 4-byte scalar values\nwithout HIST_FIELD_FL_STACKTRACE.\n\nPropagate HIST_FIELD_FL_STACKTRACE to variable references and field\nvariables (whilst excluding variable aliases from per-element\nstacktrace capture), and reject any mismatch between\nHIST_FIELD_FL_STACKTRACE and field->is_stack in check_synth_field().","severity":"unknown","score":null,"published":"2026-10-28T10:35:15.577Z","modified":"2026-10-28T10:35:15.577Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/1f36e4ddd05d540f363dbaa4c23042549f15b3ef","https://git.kernel.org/stable/c/deb336ae7c7b341591a6862cf6fcfeca97c77dfd","https://git.kernel.org/stable/c/a244c241593b5b38a08f0df2cb43c26574efbdcb"],"sources":[{"name":"CVE","id":"CVE-2026-99163","modified":"2026-10-28T10:35:15.577Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-99163"}],"assessments":[],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T19:00:30.900Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}