CVE-2025-27481: Windows Telephony Service Remote Code Execution Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-08 · updated 2026-08-10
Weakness: CWE-121

Description

Stack-based buffer overflow in Windows Telephony Service allows an unauthorized attacker to execute code over a network.

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.20978 — fixed in 10.0.10240.20978
Microsoft Windows 10 1607: before 10.0.14393.7969 — fixed in 10.0.14393.7969
Microsoft Windows 10: before 10.0.17763.7136 — fixed in 10.0.17763.7136
Microsoft Windows 10: before 10.0.19044.5737 — fixed in 10.0.19044.5737
Microsoft Windows 10: before 10.0.19045.5737 — fixed in 10.0.19045.5737
Microsoft Windows 11: before 10.0.22621.5189 — fixed in 10.0.22621.5189
Microsoft Windows 11: before 10.0.22631.5189 — fixed in 10.0.22631.5189
Microsoft Windows 11: before 10.0.26100.3775 — fixed in 10.0.26100.3775
Microsoft Windows Server 2008: r2-sp1
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.7969 — fixed in 10.0.14393.7969
Microsoft Windows Server 2019: before 10.0.17763.7136 — fixed in 10.0.17763.7136
Microsoft Windows Server 2022: before 10.0.20348.3453 — fixed in 10.0.20348.3453
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1551 — fixed in 10.0.25398.1551
Microsoft Windows Server 2025: before 10.0.26100.3775 — fixed in 10.0.26100.3775
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.20978 — fixed in 10.0.10240.20978
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.7969 — fixed in 10.0.14393.7969
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.7136 — fixed in 10.0.17763.7136
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.5737 — fixed in 10.0.19044.5737
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.5737 — fixed in 10.0.19045.5737
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.5189 — fixed in 10.0.22621.5189
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.5189 — fixed in 10.0.22631.5189
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.5189 — fixed in 10.0.22631.5189
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.3775 — fixed in 10.0.26100.3775
Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0 before 6.1.7601.27670 — fixed in 6.1.7601.27670
Microsoft Windows Server 2008 Service Pack 2: from 6.0.6003.0 before 6.0.6003.23220 — fixed in 6.0.6003.23220
Microsoft Windows Server 2012: from 6.2.9200.0 before 6.2.9200.25423 — fixed in 6.2.9200.25423
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.22523 — fixed in 6.3.9600.22523
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.7969 — fixed in 10.0.14393.7969
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.7136 — fixed in 10.0.17763.7136

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.20978; Microsoft Windows 10 1607 10.0.14393.7969; Microsoft Windows 10 10.0.17763.7136; Microsoft Windows 10 10.0.19044.5737; Microsoft Windows 10 10.0.19045.5737; Microsoft Windows 11 10.0.22621.5189; Microsoft Windows 11 10.0.22631.5189; Microsoft Windows 11 10.0.26100.3775; Microsoft Windows Server 2016 10.0.14393.7969; Microsoft Windows Server 2019 10.0.17763.7136; Microsoft Windows Server 2022 10.0.20348.3453; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1551. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-27481

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