{"id":"CVE-2026-89587","title":"ACPI: pfr_update: fix stack buffer overflow in query_capability()","summary":"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[1…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-120"],"vendor":"Linux","product":"Linux","affected":["Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < d3af83e327565a9444cebc0db714cb837e493046","Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < c5a31b4e7e37c92550be9a2edf51ca853a4d251a","Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < a2151624b55029dad0ca7efd17fb83a0461c8843","Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < 6d4ed2fd022bc862b156e53aae163b61259e1caa","Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < 15d2b7f38f95d28652170344f39ee492c55e567c","Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < ced45be0073a8a31b30b4a7f68cd3a15734515de","Linux 5.17"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:49:19.962Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89587","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"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89587.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89587"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532213"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89587"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89587"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89587.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00143,"epssPercentile":0.0355,"scores":{"cna":7.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.451Z","slug":"CVE-2026-89587","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < d3af83e327565a9444cebc0db714cb837e493046`\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < c5a31b4e7e37c92550be9a2edf51ca853a4d251a`\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < a2151624b55029dad0ca7efd17fb83a0461c8843`\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < 6d4ed2fd022bc862b156e53aae163b61259e1caa`\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < 15d2b7f38f95d28652170344f39ee492c55e567c`\n- `Linux >= 0db89fa243e5edc5de38c88b369e4c3755c5fb74 < ced45be0073a8a31b30b4a7f68cd3a15734515de`\n- `Linux 5.17`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89587.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224695,"id":"CVE-2026-89587","ts":1792401476485,"field":"cvss","old":"7","new":"7.8"},{"seq":208452,"id":"CVE-2026-89587","ts":1790005705131,"field":"cvss","old":"7.8","new":"7"},{"seq":197886,"id":"CVE-2026-89587","ts":1789384320813,"field":"cvss","old":"5.7","new":"7.8"},{"seq":197885,"id":"CVE-2026-89587","ts":1789384320813,"field":"severity","old":"medium","new":"high"},{"seq":183445,"id":"CVE-2026-89587","ts":1789356675397,"field":"cvss","old":"7.8","new":"5.7"},{"seq":183444,"id":"CVE-2026-89587","ts":1789356675397,"field":"severity","old":"high","new":"medium"},{"seq":153406,"id":"CVE-2026-89587","ts":1789285350385,"field":"cvss","old":null,"new":"7.8"},{"seq":153405,"id":"CVE-2026-89587","ts":1789285350385,"field":"severity","old":"none","new":"high"},{"seq":147552,"id":"CVE-2026-89587","ts":1789270211355,"field":"cvss","old":null,"new":"5.7"},{"seq":147551,"id":"CVE-2026-89587","ts":1789270211355,"field":"severity","old":"none","new":"medium"},{"seq":109308,"id":"CVE-2026-89587","ts":1789183731368,"field":"cvss","old":null,"new":"5.7"},{"seq":109307,"id":"CVE-2026-89587","ts":1789183731368,"field":"severity","old":"none","new":"medium"}]}