Cyber Posture

CVE-2025-21378

High

Published: 14 January 2025

Published
14 January 2025
Modified
17 January 2025
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0046 64.4th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21378 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 35.6% 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 Privilege Escalation (T1068). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Requires timely patching of the heap-based buffer overflow vulnerability in the Windows CSC Service to prevent local privilege escalation.

prevent

Employs memory protection methods like ASLR and DEP to mitigate exploitation of the heap-based buffer overflow in the CSC Service.

prevent

Enforces least privilege on the CSC Service and related processes to limit the potential impact and scope of privilege escalation from a low-privileged attacker.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Local privilege escalation via heap-based buffer overflow in Windows CSC Service enabling SYSTEM access from low-privileged context.

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

NVD Description

Windows CSC Service Elevation of Privilege Vulnerability

Deeper analysisAI

CVE-2025-21378 is an Elevation of Privilege vulnerability in the Windows CSC (Client-Side Caching) Service. It carries a CVSS v3.1 base score of 7.8, with a vector of AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, and is associated with CWE-122 (Heap-based Buffer Overflow) or related issues per NVD-CWE-noinfo. The vulnerability affects Windows operating systems where the CSC Service is present, allowing improper handling that leads to privilege escalation.

A low-privileged local attacker can exploit this vulnerability with low attack complexity and no user interaction required. Successful exploitation enables the attacker to elevate privileges, potentially gaining high-impact control over confidentiality, integrity, and availability of the system, such as achieving SYSTEM-level access from a standard user context.

Microsoft's security advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21378 provides details on patches and mitigation guidance for this vulnerability, published on 2025-01-14. Security practitioners should consult the update guide for applicable fixes across supported Windows versions.

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 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.7699
+4 more product configuration(s) — see NVD for full list

CVEs Like This One

CVE-2025-24995Same product: Microsoft Windows 10 1507
CVE-2025-24067Same product: Microsoft Windows 10 1507
CVE-2025-21418Same product: Microsoft Windows 10 1607
CVE-2025-26634Same product: Microsoft Windows 10 1507
CVE-2026-26180Same product: Microsoft Windows 10 1607
CVE-2026-20840Same product: Microsoft Windows 10 1607
CVE-2026-20922Same product: Microsoft Windows 10 1607
CVE-2026-20820Same product: Microsoft Windows 10 1607
CVE-2026-26176Same product: Microsoft Windows 10 1607
CVE-2026-25188Same product: Microsoft Windows 10 1607

References