CVE-2026-25188: Windows Telephony Service Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Elevation of Privilege
Exploit Status
Not Exploited
Exploitation Likelihood
Unlikely
Patch Tuesday
2026-Mar
Released
2026-03-10
EPSS Score
0.08% (percentile: 23.9%)

Description

Heap-based buffer overflow in Windows Telephony Service allows an unauthorized attacker to elevate privileges over an adjacent network.

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. According to the CVSS metric, the attack vector is adjacent (AV:A). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires that an attacker needs to be in the same restricted Active Directory domain as the target system. The attack surface is not reachable from broader networks, which is why the attack vector is considered adjacent (AV:A). How could an attacker exploit this vulnerability? An attacker could exploit this vulnerability by sending specially crafted malicious traffic to a vulnerable server.

Affected Products (31)

Windows

  • Windows 11 Version 26H1 for ARM64-based Systems
  • Windows 11 version 26H1 for x64-based Systems
  • Windows 10 Version 1809 for 32-bit Systems
  • Windows 10 Version 1809 for x64-based Systems
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows 10 Version 21H2 for 32-bit Systems
  • Windows 10 Version 21H2 for ARM64-based Systems
  • Windows 10 Version 21H2 for x64-based Systems
  • Windows Server 2025 (Server Core installation)
  • Windows 11 Version 25H2 for ARM64-based Systems
  • Windows 11 Version 25H2 for x64-based Systems
  • Windows 11 Version 23H2 for ARM64-based Systems
  • Windows 11 Version 23H2 for x64-based Systems
  • Windows Server 2022, 23H2 Edition (Server Core installation)
  • Windows 11 Version 24H2 for ARM64-based Systems
  • Windows 11 Version 24H2 for x64-based Systems
  • Windows Server 2025
  • Windows 10 Version 1607 for 32-bit Systems
  • Windows 10 Version 1607 for x64-based Systems
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)

ESU

  • Windows 10 Version 22H2 for x64-based Systems
  • Windows 10 Version 22H2 for ARM64-based Systems
  • Windows 10 Version 22H2 for 32-bit Systems
  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)

Security Updates (12)

Acknowledgments

<a href="https://x.com/h4urek">h4urek</a> with <a href="https://secsys.fudan.edu.cn/">secsys lab</a>

Revision History

  • 2026-03-10: Information published.