Cyber Resilience

CVE-2025-27477

High

Published: 08 April 2025

Published
08 April 2025
Modified
08 July 2025
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0332 87.5th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-27477 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 12.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

A heap-based buffer overflow vulnerability, tracked as CVE-2025-27477 and assigned CWE-122 and CWE-787, affects the Windows Telephony Service. The flaw carries a CVSS 3.1 score of 8.8 and permits remote code execution when triggered over a network.

An unauthorized attacker can exploit the issue without authentication, though user interaction is required. Successful exploitation grants the attacker the ability to execute arbitrary code with the privileges of the Telephony Service, potentially leading to full system compromise.

Microsoft's advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-27477 addresses the vulnerability and supplies patch information for affected Windows versions. The associated EPSS score remains low, with a current value of 0.0332 and a peak of 0.0389.

EU & UK References

Vulnerability details

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

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

microsoft
windows 10 1507
≤ 10.0.10240.20978 · ≤ 10.0.10240.20978
microsoft
windows 10 1607
≤ 10.0.14393.7969 · ≤ 10.0.14393.7969
microsoft
windows 10 1809
≤ 10.0.17763.7136 · ≤ 10.0.17763.7136
microsoft
windows 10 21h2
≤ 10.0.19044.5737
microsoft
windows 10 22h2
≤ 10.0.19045.5737
microsoft
windows 11 22h2
≤ 10.0.22621.5189
microsoft
windows 11 23h2
≤ 10.0.22631.5189
microsoft
windows 11 24h2
≤ 10.0.26100.3775
microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
+5 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References