EUVD-2026-66834
GHSA-mqcp-4543-826g
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Local admin required to trigger SMI; scope changes because SMRAM and BIOS firmware constitute a distinct security domain below the OS.
Primary rating from Vendor (ASUS).
CVSS VectorVendor: ASUS
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
2DescriptionCVE.org
“unsupported-when-assigned.” An out-of-bounds write in the SmiFlash SMM module of ASUS FA507NU and FA507NV BIOS allows a local administrator to cause a system crash (BSOD) or BIOS corruption via a crafted software SMI (SW SMI) request with an oversized length value.Refer to the ' Security Update for ASUS FA507NV / FA507NU BIOS ' section on the ASUS Security Advisory for more information.
AnalysisAI
Out-of-bounds write in the SmiFlash SMM (System Management Mode) module affects ASUS FA507NU and FA507NV laptop BIOS firmware across all versions. A local administrator can dispatch a crafted Software SMI (SW SMI) request with an oversized length value, causing the SmiFlash handler to write beyond its allocated SMRAM buffer boundary, resulting in a system crash (BSOD) or irreversible BIOS flash corruption. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | 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. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | 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. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch version has been confirmed in the available intelligence; the 'unsupported-when-assigned' CVE designation indicates these laptop models were already past active support at time of disclosure, making an official BIOS update unlikely. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Memory Corruption
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External POC / Exploit Code
Leaving vuln.today