138 lines
8.9 KiB
JSON
138 lines
8.9 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-89436",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-09-11T19:38:34.702Z",
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"datePublished": "2026-09-11T19:43:06.732Z",
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"dateUpdated": "2026-10-19T08:46:44.750Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-10-19T08:46:44.750Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86: panasonic-laptop: Fix sentinel write past pcc->sinf[]\n\nacpi_pcc_retrieve_biosdata() rejects SINF packages only when\npcc->num_sifr is strictly less than hkey->package.count, then\nunconditionally writes a trailing sentinel at\npcc->sinf[hkey->package.count]. But pcc->sinf[] is allocated with\nexactly pcc->num_sifr elements (valid indices 0..num_sifr-1), so that\nwrite needs num_sifr strictly greater than package.count to stay in\nbounds -- num_sifr == package.count passes the existing check but\nstill overflows by one element.\n\nThis is exactly the case probe()'s existing num_sifr++ workaround\n(\"Some DSDT-s have an off-by-one bug where the SINF package count is\none higher than the SQTY reported value\") is written to accommodate:\nwhen a DSDT's SINF package count equals SQTY+1, the workaround makes\nnum_sifr equal to package.count, which is precisely the boundary that\noverflows here. Found via UBSan (array-index-out-of-bounds) on\nhardware where HKEY.SQTY returns 37 and HKEY.SINF()'s package has 38\nelements: num_sifr becomes 38 after the += 1 workaround, the loop\ncorrectly fills indices 0..37, and the sentinel write then targets\nindex 38, one past the end -- a silent 4-byte heap overflow on kernels\nwithout CONFIG_UBSAN.\n\nTightening the rejection check to num_sifr <= package.count would\navoid the overflow but breaks probe() entirely on exactly this\nhardware, since num_sifr == package.count is the case the off-by-one\nworkaround exists to support. Nothing else in the driver reads this\nsentinel value back, so simply skip the write when there is no room\nfor it instead."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The overflow is reached by reading world-readable sysfs files under /sys/bus/acpi/devices/MAT00xx:00/ (numbatt, lcdtype, mute, sticky_key, eco_mode, brightness) and /sys/class/backlight/panasonic/, which call acpi_pcc_retrieve_biosdata(); there is no network or remote-peer path into this ACPI laptop driver.\nAC:L - On Panasonic Let's Note firmware where HKEY.SINF's package count equals SQTY+1, every sysfs or backlight read deterministically writes the sentinel one past pcc->sinf[]; no race is required. That DSDT off-by-one is a fixed property of the affected hardware being scored, not a per-attempt condition.\nPR:L - The triggering attributes are DEVICE_ATTR_RO (0444) or DEVICE_ATTR_RW (0644), so any unprivileged local user can read them and cause the out-of-bounds write with no capability, group membership, or init-namespace root.\nUI:N - The attacker reads a sysfs attribute from their own process; no victim action such as mounting a filesystem, plugging hardware, or confirming a prompt is required.\nS:U - The 4-byte heap overflow corrupts host kernel slab memory belonging to the same kernel security authority that hosts the driver; it does not cross a VM, IOMMU, or sandbox boundary.\nC:H - The off-by-one writes 0xffffffff one u32 past the kzalloc_flex pcc_acpi object, corrupting adjacent kmalloc slab contents including pointers on size-class-aligned allocations; that heap corruption can be leveraged for kernel information disclosure, so confidentiality is High.\nI:H - This is a repeatable 4-byte out-of-bounds heap write of the sentinel past pcc->sinf[]. Per kernel scoring guidance an OOB write is High because heap grooming can place a security-relevant object at the overwritten offset and turn it into a control-flow or privilege primitive.\nA:H - Writing past the kmalloc object can corrupt neighboring slab objects or metadata and produce a kernel oops or panic, and debug kernels trip KASAN/UBSAN on the counted-by overflow; any such crash is Availability High."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/platform/x86/panasonic-laptop.c"
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],
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"versions": [
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{
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"version": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
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"lessThan": "a93df956ee4d903735b6d395362c839cb1dc07e3",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "a3d0dbd18ce908292607bb6cf37c978ece8a33d4",
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"lessThan": "329f10d8be193bf36af124e00b9dd6644cd71724",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/platform/x86/panasonic-laptop.c"
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],
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"versions": [
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{
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"version": "7.2",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "7.2",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2.4",
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"lessThanOrEqual": "7.2.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.3",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "7.2",
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"versionEndExcluding": "7.2.4"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "7.2",
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"versionEndExcluding": "7.3"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/a93df956ee4d903735b6d395362c839cb1dc07e3"
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},
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{
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"url": "https://git.kernel.org/stable/c/329f10d8be193bf36af124e00b9dd6644cd71724"
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}
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],
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"title": "platform/x86: panasonic-laptop: Fix sentinel write past pcc->sinf[]",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |