Cyber Posture

CVE-2025-21409

High

Published: 14 January 2025

Published
14 January 2025
Modified
16 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 0.0610 90.9th percentile
Risk Priority 21 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21409 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 9.1% 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 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly remediates the heap-based buffer overflow in Windows Telephony Service by requiring timely application of Microsoft's security patch.

prevent

Implements memory protections like ASLR, DEP, and heap isolation to prevent arbitrary code execution from heap buffer overflows.

prevent

Requires validation of network inputs to the Telephony Service to block malformed data triggering the buffer overflow.

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

The RCE vulnerability in the Windows Telephony Service requires user interaction (e.g., malicious link or file) for remote exploitation leading to arbitrary code execution, directly mapping to Exploitation for Client Execution.

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

NVD Description

Windows Telephony Service Remote Code Execution Vulnerability

Deeper analysisAI

CVE-2025-21409 is a Remote Code Execution vulnerability in the Windows Telephony Service. Published on 2025-01-14, 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-122, indicating a heap-based buffer overflow with insufficient additional details from NVD-CWE.

The vulnerability can be exploited by a remote unauthenticated attacker over the network with low attack complexity, though it requires user interaction such as clicking a malicious link or file. Successful exploitation enables the attacker to achieve high impacts on confidentiality, integrity, and availability, allowing arbitrary code execution on the targeted Windows system.

Microsoft's update guide provides details on mitigation, available at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21409.

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
≤ 10.0.22621.4751 · ≤ 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-2025-21266Same product: Microsoft Windows 10 1507
CVE-2025-21407Same product: Microsoft Windows 10 1507
CVE-2025-21303Same product: Microsoft Windows 10 1507
CVE-2025-21339Same product: Microsoft Windows 10 1507
CVE-2025-21233Same product: Microsoft Windows 10 1507
CVE-2025-21371Same product: Microsoft Windows 10 1507
CVE-2025-21240Same product: Microsoft Windows 10 1507
CVE-2025-59295Same product: Microsoft Windows 10 1507
CVE-2025-21239Same product: Microsoft Windows 10 1507
CVE-2025-24056Same product: Microsoft Windows 10 1507

References