ASUS FA507 BIOS CVE-2026-19398

Exploitation requires a local administrator account (or equivalent privilege level capable of dispatching kernel-mode SMI requests) on a device running ASUS FA507NV or FA507NU BIOS firmware. On Windows, triggering a Software SMI programmatically requires kernel-mode execution, meaning an attacker must either already have administrator privileges sufficient to load a driver, or chain this with a separate privilege-escalation step. The flaw is hardware-model-specific and does not generalize to other ASUS products. No network-reachable attack surface exists - the attack vector is strictly local (AV:L). No user interaction beyond the attacker's own session is required. Exploitation is constrained by: the high privilege prerequisite (PR:H), the narrow product scope (two specific laptop SKUs), and the 'unsupported-when-assigned' status limiting the likely active install base.

The CVSS 4.0 score of 6.8 accurately reflects the attack profile: local access (AV:L) with high privilege requirements (PR:H) substantially limits exploitability to scenarios where an attacker already controls an administrative session on the physical or remotely-administered device. No EPSS data was included in the provided intelligence, no CISA KEV listing exists, and no public exploit code has been identified, placing real-world exploitation probability in the low range based on available signals. The integrity and availability impacts are each rated high (VI:H, VA:H) because BIOS flash corruption can render the device unbootable - a severe and potentially irreversible outcome. The most consequential risk factor is the 'unsupported-when-assigned' designation: these models were already out of active vendor support when the CVE was assigned, meaning a remediation release is unlikely, leaving affected units permanently exposed. For most organizations this represents a low operational priority given the narrow, consumer-laptop product scope; however, any IT environment managing these specific models should treat the absence of a patch path - not merely the CVSS score - as the governing risk signal.

An attacker with local administrator rights on a target FA507NU or FA507NV laptop writes or executes a kernel-mode driver or privileged utility that dispatches a Software SMI request to the SmiFlash handler with a crafted length value larger than the allocated SMRAM buffer. The handler processes the request without bounds checking and writes past the buffer boundary, corrupting adjacent SMRAM. The immediate outcome is a system crash (BSOD); if flash memory metadata is overwritten, the device may fail to boot on next power cycle, resulting in permanent BIOS corruption without physical recovery access.