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PatchSiren cyber security CVE debrief

CVE-2026-83849 Microsoft CVE debrief

A Windows Hello information disclosure vulnerability exists due to an out-of-bounds read in Windows Hello, allowing an authorized attacker to disclose information locally. Multiple Windows versions are affected, including Windows 10 Version 21H2, Windows 10 Version 22H2, and various Windows 11 versions. Defenders should assess exposure and apply patches from Microsoft. The vulnerability allows an attacker to disclose information locally, and defenders should prioritize verifying exposure in Windows Hello configurations.

Vendor
Microsoft
Product
Windows 10 Version 21H2
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 Hello, should assess exposure and apply patches from Microsoft. This includes reviewing Windows Hello configurations, verifying exposure, and applying patches. Additionally, defenders should monitor Windows systems for updates and ensure that affected systems are properly mitigated.

Why it matters

CVE-2026-83849 is a Windows Hello information disclosure vulnerability that allows an authorized attacker to disclose information locally. Defenders should prioritize verifying exposure in Windows Hello configurations and applying patches from Microsoft.

  • Verify and apply patches to prevent information disclosure
  • Assess exposure in Windows Hello configurations
  • Monitor Windows systems for updates

Technical summary

An out-of-bounds read in Windows Hello allows an authorized attacker to disclose information locally. Affected versions include Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, and Windows 11 Version 26H2.

Defensive priority

Defenders should prioritize verifying exposure in Windows Hello configurations and applying patches from Microsoft.

Recommended defensive actions

  • Verify exposure in Windows Hello configurations
  • Apply patches from Microsoft
  • Monitor Windows systems for updates

Evidence notes

The CVE record and source item provide details on the vulnerability and affected Windows versions. Microsoft has released a patch for this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-83849 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-83849

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

  • CVE-2026-83849 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-83849

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

Supplemental references

  • Windows Hello Information Disclosure Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/83xxx/CVE-2026-83849.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83849

    Supplemental source - vendor-advisory, patch

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.