Full Report
Microsoft has fixed a known issue causing "boot device inaccessible" errors during startup on some Windows Server 2025 systems using iSCSI. [...]
Analysis Summary
This summary is based on the provided context, noting that the information details a functional bug fix rather than a typical security vulnerability involving exploitation, as no CVE was explicitly mentioned.
# Vulnerability: Windows Server 2025 iSCSI Boot Failure After Installation
## CVE Details
- CVE ID: Not applicable (Described as a product issue/bug fix, no CVE identifier provided)
- CVSS Score: Not applicable
- CWE: Not applicable
## Affected Systems
- Products: Windows Server 2025
- Versions: Post-installation instances experiencing the startup failure.
- Configurations: Servers operating under **NDIS Poll Mode** booting from an **iSCSI LUN**.
## Vulnerability Description
A bug in Windows Server 2025 causes systems configured to use NDIS Poll Mode while booting from an iSCSI LUN to render the boot device inaccessible, resulting in a startup failure immediately following the completion of OS installation.
## Exploitation
- Status: Not applicable (Functional bug, not a security vulnerability)
- Complexity: Not applicable
- Attack Vector: Not applicable
## Impact
- Confidentiality: Minimal/None (Functional failure)
- Integrity: Minimal/None (Functional failure)
- Availability: High (System becomes unbootable)
## Remediation
### Patches
- **KB5051987**: Installed via Windows updates released on or after February 11, 2025. Microsoft recommends installing the latest update available.
### Workarounds
- No specific workarounds were detailed in the context, as the issue was resolved via the stated updates.
## Detection
- **Indicators of Compromise**: "boot device inaccessible" error during startup.
- **Detection methods and tools**: Monitoring for the specific boot failure on newly installed Server 2025 instances using the affected iSCSI/NDIS configuration.
## References
- Vendor advisories: Microsoft acknowledgement (Late October context)
- Relevant links - defanged:
- [https://www.bleepingcomputer.com/news/microsoft/microsoft-february-2025-patch-tuesday-fixes-4-zero-days-55-flaws/]