CVE-2026-56173: Microsoft Windows WebView use after free privilege escalation

CVE-2026-56173 · Severity: high · CVSS 7 · Published 2026-07-14

A security vulnerability exists in Windows WebView, a component used by many applications to display web content. An attacker who already has basic access to a computer could exploit this flaw to gain higher-level administrative privileges. This could allow them to take full control of the system, access sensitive data, or bypass security restrictions.

Technologies: Microsoft Windows 11, Microsoft Windows 10, Microsoft Windows Server 2019. Vendors: Microsoft.

Quick answers

Is CVE-2026-56173 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-56173 being exploited in the wild.
How severe is CVE-2026-56173?
High severity, with a CVSS score of 7, published 14 July 2026.
Which products and versions are affected?
Microsoft Windows 11 10.0.22631.0 to 10.0.22631.7376; Microsoft Windows 10 10.0.17763.0 to 10.0.17763.9020; Microsoft Windows Server 2019 10.0.17763.0 to 10.0.17763.9020.
Is there a fix for CVE-2026-56173?
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-2026-56173 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-56173?
Check whether you run Microsoft Windows 11, Microsoft Windows 10 or Microsoft Windows Server 2019 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

A use-after-free (UAF) vulnerability exists in the Windows WebView component (CWE-416). The flaw is triggered when the system attempts to access memory that has already been deallocated, leading to memory corruption. An attacker with low-privileged local access can exploit this condition to execute code with elevated privileges. The attack requires a local presence and is characterized by high complexity, but it does not require user interaction. Microsoft has released security updates to address this issue across various versions of Windows 10, Windows 11, and Windows Server.

Affected products

  • 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 23H2 10.0.22631.0 to 10.0.22631.7376
  • Microsoft Windows 11 Version 24H2 10.0.26100.0 to 10.0.26100.8875
  • Microsoft Windows 11 Version 25H2 10.0.26200.0 to 10.0.26200.8875
  • Microsoft Windows 11 Version 26H1 10.0.28000.0 to 10.0.28000.2269
  • Microsoft Windows Server 2019 10.0.17763.0 to 10.0.17763.9020

Timeline

  • 2026-07-14: disclosed: Initial publication of the vulnerability details.
  • 2026-07-14: advisory: Microsoft released the Security Update Guide for this CVE.

References

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