{"id":"CVE-2026-89587","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89587","summary":"ACPI: pfr_update: fix stack buffer overflow in query_capability()","details":"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.","published":"2026-09-11T19:44:52.066Z","modified":"2026-09-14T03:46:16.178754556Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a2151624b55029dad0ca7efd17fb83a0461c8843"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89587.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89587"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:16.178754556Z"}}