{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89587", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.729Z", "datePublished": "2026-09-11T19:44:52.066Z", "dateUpdated": "2026-10-19T08:49:19.962Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:49:19.962Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nACPI: pfr_update: fix stack buffer overflow in query_capability()\n\nquery_capability() copies four ACPI buffer objects returned by the\nfirmware _DSM into fixed-size u8[16] fields in struct\npfru_update_cap_info using memcpy with the firmware-supplied length:\n\n memcpy(&cap_hdr->code_type,\n elements[CAP_CODE_TYPE_IDX].buffer.pointer,\n elements[CAP_CODE_TYPE_IDX].buffer.length);\n\nThe same pattern repeats for drv_type, platform_id, and oem_id.\nIf the firmware returns buffer.length > 16 for any of these fields,\nmemcpy writes past the destination array.\n\nstruct pfru_update_cap_info is stack-allocated in pfru_ioctl().\n\nConfirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports\nare generated when a DSM returns 64-byte buffers, with writes reaching\n44 bytes past the end of cap_hdr's [64, 156) frame window into\nadjacent stack redzones.\n\nIntroduce a helper pointer to out_obj->package.elements and use it\nto validate each buffer length against its destination field size\nbefore copying, returning -EINVAL if the firmware supplies an\noversized buffer." } ], "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 - The overflow is reached only via local ioctl(PFRU_IOC_QUERY_CAP) or write() on /dev/acpi_pfr_updateN (pfru_ioctl/pfru_write → query_capability). No network, Bluetooth, USB, or packet path evaluates this ACPI _DSM copy.\nAC:L - A single ioctl or write deterministically copies firmware-supplied _DSM buffer lengths into 16-byte stack fields; KASAN reproduced 64-byte DSM buffers writing 44 bytes past cap_hdr. No race or attacker-uncontrollable memory layout is required.\nPR:L - The ioctl/write path has no capable() or namespace check; access is only DAC on the misc device. Although pfrut checks uid 0 and devtmpfs defaults to 0600, Intel PFRU servers reasonably grant /dev/acpi_pfr_updateN to a firmware-management account or container, so privileges are Low.\nUI:N - The attacker opens the device and issues PFRU_IOC_QUERY_CAP or write() themselves; no separate victim action such as mounting a filesystem or opening a hostile file is required.\nS:U - The overflow corrupts the calling task's kernel stack inside the host kernel. This is local privilege escalation within one security authority, not a VM escape, IOMMU bypass, or sandbox breakout.\nC:H - Firmware-controlled memcpy overflows four u8[16] stack fields and adjacent frame state (KASAN: 44 bytes past cap_hdr), which per kernel guidance is memory corruption leverageable for arbitrary kernel memory disclosure.\nI:H - This is a kernel stack buffer overflow of firmware-controlled length and contents into stack-allocated struct pfru_update_cap_info, overwriting saved registers and the return address and enabling control-flow hijacking.\nA:H - The same out-of-bounds stack writes were confirmed by KASAN and can oops, trip the stack protector, or panic the kernel; the ioctl can be repeated to deny availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/acpi/pfr_update.c" ], "versions": [ { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "d3af83e327565a9444cebc0db714cb837e493046", "status": "affected", "versionType": "git" }, { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "c5a31b4e7e37c92550be9a2edf51ca853a4d251a", "status": "affected", "versionType": "git" }, { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "a2151624b55029dad0ca7efd17fb83a0461c8843", "status": "affected", "versionType": "git" }, { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "6d4ed2fd022bc862b156e53aae163b61259e1caa", "status": "affected", "versionType": "git" }, { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "15d2b7f38f95d28652170344f39ee492c55e567c", "status": "affected", "versionType": "git" }, { "version": "0db89fa243e5edc5de38c88b369e4c3755c5fb74", "lessThan": "ced45be0073a8a31b30b4a7f68cd3a15734515de", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/acpi/pfr_update.c" ], "versions": [ { "version": "5.17", "status": "affected" }, { "version": "0", "lessThan": "5.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "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": "5.17", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d3af83e327565a9444cebc0db714cb837e493046" }, { "url": "https://git.kernel.org/stable/c/c5a31b4e7e37c92550be9a2edf51ca853a4d251a" }, { "url": "https://git.kernel.org/stable/c/a2151624b55029dad0ca7efd17fb83a0461c8843" }, { "url": "https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa" }, { "url": "https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c" }, { "url": "https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de" } ], "title": "ACPI: pfr_update: fix stack buffer overflow in query_capability()", "x_generator": { "engine": "bippy-1.2.0" } } } }