Advisory · CVE-2026-97805
Out-of-bounds read in Windows Partition Management Driver rated 9.8
The Windows Partition Management Driver has an out-of-bounds read Microsoft scores 9.8, describing it as allowing an unauthorized attacker to execute code over a network. Microsoft rates it CVSS 3.1 9.8.
- Vendor
- Microsoft
- Product
- Windows Partition Management Driver
- Identifier / CWE
- CVE-2026-97805
CWE-125 - Action timing
- Immediate
Explain it like I’m five
The driver that maps out disk partitions reads past the end of its data, and Microsoft scores the result as a path to code execution.
- 01Reach the component
An unauthenticated attacker sends crafted network traffic to a Windows system running Windows Partition Management Driver.
- 02Memory flaw triggers
The component mishandles the input and corrupts or reuses memory outside its intended bounds.
- 03Code runs
The attacker gains code execution in the component's context on the target system.
What happened
Microsoft disclosed CVE-2026-97805 in its October 2026 update guide: an out-of-bounds read (CWE-125, with CWE-20 also listed) in the Windows Partition Management Driver, scored 9.8 with high impact across confidentiality, integrity, and availability.
Microsoft lists the affected Windows releases in its update guide. Apply the October 2026 security updates for your release rather than relying on a version guess here.
What to do
- Inventory every Windows Partition Management Driver deployment, including test, training, and individually managed instances.
- Apply the vendor fix or upgrade exactly as directed in the linked vendor bulletin or advisory.
- Restrict network access to Windows Partition Management Driver while remediation is underway, especially for internet-facing instances.
- Review application and server logs for storage driver crashes, disk errors outside hardware faults, and unexpected partition changes.
- Check for accounts, content, or configuration created outside normal change processes, and rotate exposed credentials where access cannot be ruled out.
- Verify the deployed version or patch level after remediation.
Management note
Storage drivers sit below almost every protection the OS offers. Include them in the urgent patch ring.