{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99163", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.398Z", "datePublished": "2026-10-28T10:35:15.577Z", "dateUpdated": "2026-10-31T12:44:20.055Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-31T12:44:20.055Z" }, "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()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Local writes to tracefs synthetic_events and events/.../trigger supply the bad field/action; event_trigger_write() → event_hist_trigger_parse() → create_actions() → the patched check_synth_field(). No network or physical input reaches it.\nAC:L - The attacker can deterministically create the stack field, map an 8-byte signed scalar or expression to it, enable the synthetic event, and issue their own triggering syscall; no race or uncontrollable state is required.\nPR:L - Although these files are mode 0640, tracefs_parse_param() accepts uid= and tracefs_apply_options() propagates that owner to synthetic_events and eventfs trigger files, allowing a delegated non-root tracing account to write both; user namespaces alone cannot mount tracefs.\nUI:N - The attacker performs every required tracefs write and triggers the configured histogram through their own syscall or selected tracepoint, without another user's action.\nS:U - The invalid pointer dereference and ring-buffer overwrite occur entirely within the host kernel's tracing subsystem and do not cross a VM, IOMMU, or separate security authority.\nC:H - An 8-byte signed histogram expression can hold a chosen address; get_field_size() dereferences it and trace_stack() copies up to 16 machine words into a synthetic-event record readable from the trace buffer, permitting repeatable kernel-memory disclosure.\nI:H - get_field_size() sizes the record from the pointer's first word, while trace_stack() independently scans up to 16 nonzero words before memcpy(); a mismatched count therefore writes past the reserved ring-buffer record.\nA:H - Mapping raw_syscalls:sys_enter.id directly to the stack field makes get_field_size() dereference a small invalid address on the attacker's next syscall, producing a deterministic, repeatable kernel oops." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_hist.c" ], "versions": [ { "version": "b9453380c1c542fd095a4dbe9251eeba4022bbce", "lessThan": "eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5", "status": "affected", "versionType": "git" }, { "version": "5f52389bdd9eafb63b3a2f804e02aeb17b6a5f55", "lessThan": "326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be", "status": "affected", "versionType": "git" }, { "version": "f3baa42afeea0d5f04ad31525e861199d02210cc", "lessThan": "6c4e4946febb585d2fc93a02a0cd12cec715bb32", "status": "affected", "versionType": "git" }, { "version": "00cf3d672a9dd409418647e9f98784c339c3ff63", "lessThan": "7e0d05a6234a984ac23b8a563fb7f66f2572b668", "status": "affected", "versionType": "git" }, { "version": "00cf3d672a9dd409418647e9f98784c339c3ff63", "lessThan": "648687f2b448d8527cd7b112fe5d4bd0fec85a87", "status": "affected", "versionType": "git" }, { "version": "00cf3d672a9dd409418647e9f98784c339c3ff63", "lessThan": "1f36e4ddd05d540f363dbaa4c23042549f15b3ef", "status": "affected", "versionType": "git" }, { "version": "00cf3d672a9dd409418647e9f98784c339c3ff63", "lessThan": "deb336ae7c7b341591a6862cf6fcfeca97c77dfd", "status": "affected", "versionType": "git" }, { "version": "00cf3d672a9dd409418647e9f98784c339c3ff63", "lessThan": "a244c241593b5b38a08f0df2cb43c26574efbdcb", "status": "affected", "versionType": "git" }, { "version": "5.10.237", "lessThan": "5.10.273", "status": "affected", "versionType": "semver" }, { "version": "5.15.124", "lessThan": "5.15.224", "status": "affected", "versionType": "semver" }, { "version": "6.1.43", "lessThan": "6.1.191", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_hist.c" ], "versions": [ { "version": "6.3", "status": "affected" }, { "version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.273", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.59", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.13", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "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" } ] } ] } ], "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" } ], "title": "tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields", "x_generator": { "engine": "bippy-1.2.0" } } } }