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PatchSiren cyber security CVE debrief

CVE-2026-70277 Microsoft CVE debrief

A Windows Fast FAT File System Driver Information Disclosure Vulnerability exists, allowing an unauthorized attacker to disclose information locally due to an out-of-bounds read in the Windows Fast FAT Driver. This vulnerability affects various Windows 10, Windows 11, and Windows Server versions. Defenders should assess exposure and apply patches from Microsoft. The vulnerability allows local information disclosure, requiring patch verification and application, as well as system log monitoring.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-13
Advisory published
2026-10-13
Advisory updated
2026-10-13

Who should care

Defenders responsible for Windows systems, particularly those using Windows 10, Windows 11, and Windows Server versions, should assess exposure and apply patches.

Why it matters

CVE-2026-70277 is a Windows Fast FAT File System Driver Information Disclosure Vulnerability. Defenders should care because it allows local information disclosure, requires patch verification and application, and system log monitoring. Affected systems include various Windows 10, Windows 11, and Windows Server versions.

  • Local information disclosure possible.
  • Patch verification and application required.
  • System log monitoring recommended.

Technical summary

The Windows Fast FAT File System Driver is vulnerable to an out-of-bounds read, allowing an unauthorized attacker to disclose information locally. The vulnerability is caused by a lack of proper bounds checking in the driver, which can be exploited by a local attacker to access sensitive information. Microsoft has released a patch for this issue, which defenders should verify and apply to prevent exploitation.

Defensive priority

Defenders should prioritize verifying and applying patches from Microsoft, as this vulnerability could potentially allow local information disclosure.

Recommended defensive actions

  • Verify and apply patches from Microsoft for the Windows Fast FAT File System Driver.
  • Conduct a thorough review of system configurations and update affected systems.
  • Monitor system logs for potential exploitation attempts.

Evidence notes

The CVE Program and NVD provide official records of this vulnerability. Microsoft has released a patch for this issue. The vulnerability has been publicly disclosed and defenders should verify and apply the patch to prevent local information disclosure. The CVE record was published on 2026-10-13T19:00:14.148Z and has not been modified since then. There are no known instances of exploitation.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-70277 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-70277

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-70277 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-70277

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.