CVE-2026-89587
CVE-2026-89587 is a remote code execution vulnerability. O3 Security confirms whether CVE-2026-89587 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In the Linux kernel, the following vulnerability has been resolved: ACPI: pfr_update: fix stack buffer overflow in query_capability() query_capability() copies four ACPI buffer objects…
Description
In the Linux kernel, the following vulnerability has been resolved:
ACPI: pfr_update: fix stack buffer overflow in query_capability()
query_capability() copies four ACPI buffer objects returned by the firmware _DSM into fixed-size u8[16] fields in struct pfru_update_cap_info using memcpy with the firmware-supplied length:
memcpy(&cap_hdr->code_type, elements[CAP_CODE_TYPE_IDX].buffer.pointer, elements[CAP_CODE_TYPE_IDX].buffer.length);
The same pattern repeats for drv_type, platform_id, and oem_id. If the firmware returns buffer.length > 16 for any of these fields, memcpy writes past the destination array.
struct pfru_update_cap_info is stack-allocated in pfru_ioctl().
Confirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports are generated when a DSM returns 64-byte buffers, with writes reaching 44 bytes past the end of cap_hdr's [64, 156) frame window into adjacent stack redzones.
Introduce a helper pointer to out_obj->package.elements and use it to validate each buffer length against its destination field size before copying, returning -EINVAL if the firmware supplies an oversized buffer.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-89587 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-89587 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-89587. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-89587 in your dependencies?
O3 detects CVE-2026-89587 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.