CVE-2026-57091: Microsoft Windows File History Service stack overflow privilege escalation

CVE-2026-57091 · Severity: high · CVSS 7.8 · Published 2026-07-14

A security vulnerability exists in the Windows File History Service, a component used to automatically back up user files. An attacker who already has basic access to a computer could exploit this flaw to gain full administrative control over the system. This could allow them to access sensitive data, install malicious software, or disrupt business operations.

Technologies: Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809, Microsoft Windows 10 Version 21H2, Microsoft Windows 10 Version 22H2, Microsoft Windows 11 Version 24H2, Microsoft Windows Server 2016. Vendors: Microsoft.

Quick answers

Is CVE-2026-57091 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-57091 being exploited in the wild.
How severe is CVE-2026-57091?
High severity, with a CVSS score of 7.8, published 14 July 2026.
Which products and versions are affected?
Microsoft Windows 10 Version 1607 10.0.14393.0 to 10.0.14393.9339; Microsoft Windows 10 Version 1809 10.0.17763.0 to 10.0.17763.9020; Microsoft Windows 10 Version 21H2 10.0.19044.0 to 10.0.19044.7548; Microsoft Windows 10 Version 22H2 10.0.19045.0 to 10.0.19045.7548; and 2 more.
Is there a fix for CVE-2026-57091?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-57091 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-57091?
Check whether you run Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809, Microsoft Windows 10 Version 21H2 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

This vulnerability is classified as a stack-based buffer overflow (CWE-121) within the Windows File History Service. The flaw is triggered when the service improperly handles specific data inputs, leading to memory corruption. An attacker with low-privileged local access can exploit this to execute arbitrary code with elevated system privileges. The attack vector is local, requiring no user interaction, and affects multiple versions of Windows 10, Windows 11, and Windows Server. Microsoft has released security updates to address this issue.

Affected products

  • Microsoft Windows 10 Version 1607 10.0.14393.0 to 10.0.14393.9339
  • Microsoft Windows 10 Version 1809 10.0.17763.0 to 10.0.17763.9020
  • Microsoft Windows 10 Version 21H2 10.0.19044.0 to 10.0.19044.7548
  • Microsoft Windows 10 Version 22H2 10.0.19045.0 to 10.0.19045.7548
  • Microsoft Windows 11 Version 24H2 10.0.26100.0 to 10.0.26100.8875
  • Microsoft Windows Server 2016 10.0.14393.0 to 10.0.14393.9339

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory

References

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