{"id":"CVE-2026-99163","state":"PUBLISHED","title":"tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields","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().","publishedAt":"2026-10-28T10:35:15.577Z","updatedAt":"2026-10-30T12:42:29.139Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b9453380c1c542fd095a4dbe9251eeba4022bbce","status":"affected","lessThan":"eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5","versionType":"git"},{"version":"5f52389bdd9eafb63b3a2f804e02aeb17b6a5f55","status":"affected","lessThan":"326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be","versionType":"git"},{"version":"f3baa42afeea0d5f04ad31525e861199d02210cc","status":"affected","lessThan":"6c4e4946febb585d2fc93a02a0cd12cec715bb32","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"7e0d05a6234a984ac23b8a563fb7f66f2572b668","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"648687f2b448d8527cd7b112fe5d4bd0fec85a87","versionType":"git"},{"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":"5.10.237","status":"affected","lessThan":"5.10.273","versionType":"semver"},{"version":"5.15.124","status":"affected","lessThan":"5.15.224","versionType":"semver"},{"version":"6.1.43","status":"affected","lessThan":"6.1.191","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","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"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]}],"references":["https://git.kernel.org/stable/c/eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5","https://git.kernel.org/stable/c/326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be","https://git.kernel.org/stable/c/6c4e4946febb585d2fc93a02a0cd12cec715bb32","https://git.kernel.org/stable/c/7e0d05a6234a984ac23b8a563fb7f66f2572b668","https://git.kernel.org/stable/c/648687f2b448d8527cd7b112fe5d4bd0fec85a87","https://git.kernel.org/stable/c/1f36e4ddd05d540f363dbaa4c23042549f15b3ef","https://git.kernel.org/stable/c/deb336ae7c7b341591a6862cf6fcfeca97c77dfd","https://git.kernel.org/stable/c/a244c241593b5b38a08f0df2cb43c26574efbdcb"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99163.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99163","state":"PUBLISHED","datePublished":"2026-10-28T10:35:15.577Z","dateUpdated":"2026-10-30T12:42:29.139Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.398Z"},"containers":{"cna":{"title":"tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields","descriptions":[{"lang":"en","value":"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()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b9453380c1c542fd095a4dbe9251eeba4022bbce","status":"affected","lessThan":"eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5","versionType":"git"},{"version":"5f52389bdd9eafb63b3a2f804e02aeb17b6a5f55","status":"affected","lessThan":"326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be","versionType":"git"},{"version":"f3baa42afeea0d5f04ad31525e861199d02210cc","status":"affected","lessThan":"6c4e4946febb585d2fc93a02a0cd12cec715bb32","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"7e0d05a6234a984ac23b8a563fb7f66f2572b668","versionType":"git"},{"version":"00cf3d672a9dd409418647e9f98784c339c3ff63","status":"affected","lessThan":"648687f2b448d8527cd7b112fe5d4bd0fec85a87","versionType":"git"},{"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":"5.10.237","status":"affected","lessThan":"5.10.273","versionType":"semver"},{"version":"5.15.124","status":"affected","lessThan":"5.15.224","versionType":"semver"},{"version":"6.1.43","status":"affected","lessThan":"6.1.191","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","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"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5"},{"url":"https://git.kernel.org/stable/c/326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be"},{"url":"https://git.kernel.org/stable/c/6c4e4946febb585d2fc93a02a0cd12cec715bb32"},{"url":"https://git.kernel.org/stable/c/7e0d05a6234a984ac23b8a563fb7f66f2572b668"},{"url":"https://git.kernel.org/stable/c/648687f2b448d8527cd7b112fe5d4bd0fec85a87"},{"url":"https://git.kernel.org/stable/c/1f36e4ddd05d540f363dbaa4c23042549f15b3ef"},{"url":"https://git.kernel.org/stable/c/deb336ae7c7b341591a6862cf6fcfeca97c77dfd"},{"url":"https://git.kernel.org/stable/c/a244c241593b5b38a08f0df2cb43c26574efbdcb"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:42:29.139Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.237","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.124","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.43","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}