Cyber Posture

CVE-2025-21243

High

Published: 14 January 2025

Published
14 January 2025
Modified
24 January 2025
KEV Added
Patch
CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0072 72.5th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21243 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation of Remote Services (T1210); ranked in the top 27.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 CM-7 (Least Functionality) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation of Remote Services (T1210) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly addresses the CVE by requiring timely remediation of the flaw in Windows Telephony Service through patching.

prevent

Eliminates the attack surface for this service-specific RCE vulnerability by disabling or restricting unnecessary Windows Telephony Service functionality.

prevent

Mitigates exploitation of the integer overflow leading to RCE via memory protections like DEP and ASLR.

MITRE ATT&CK Enterprise TechniquesAI

T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

RCE in Windows Telephony Service enables direct exploitation of remote services (T1210) and client execution (T1203) via network vector with user interaction.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Windows Telephony Service Remote Code Execution Vulnerability

Deeper analysisAI

CVE-2025-21243 is a Remote Code Execution vulnerability affecting the Windows Telephony Service. Published on 2025-01-14T18:15:40.180, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) and is associated with CWE-190 and NVD-CWE-noinfo.

The vulnerability enables remote exploitation over the network with low complexity and no required privileges, though it demands user interaction. An attacker who tricks a user into performing a specific action can achieve high-impact confidentiality, integrity, and availability effects, including remote code execution on the targeted system.

Mitigation details are available in the Microsoft Security Response Center update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21243.

Details

CWE(s)

Affected Products

microsoft
windows 10 1507
≤ 10.0.10240.20890 · ≤ 10.0.10240.20890
microsoft
windows 10 1607
≤ 10.0.14393.7699 · ≤ 10.0.14393.7699
microsoft
windows 10 1809
≤ 10.0.17763.6775 · ≤ 10.0.17763.6775
microsoft
windows 10 21h2
≤ 10.0.19044.5371
microsoft
windows 10 22h2
≤ 10.0.19045.5371
microsoft
windows 11 22h2
≤ 10.0.22621.4751
microsoft
windows 11 23h2
≤ 10.0.22631.4751
microsoft
windows 11 24h2
≤ 10.0.26100.2894
microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
+5 more product configuration(s) — see NVD for full list

CVEs Like This One

CVE-2025-21244Same product: Microsoft Windows 10 1507
CVE-2025-21338Same product: Microsoft Windows 10 1507
CVE-2025-21245Same product: Microsoft Windows 10 1507
CVE-2025-21237Same product: Microsoft Windows 10 1507
CVE-2025-21406Same product: Microsoft Windows 10 1507
CVE-2025-53143Same product: Microsoft Windows 10 1507
CVE-2025-21266Same product: Microsoft Windows 10 1507
CVE-2025-21296Same product: Microsoft Windows 10 1507
CVE-2025-21201Same product: Microsoft Windows 10 1507
CVE-2025-21223Same product: Microsoft Windows 10 1507

References