Windows
CVE-2025-24985
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Heap buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 7.8 (High). KEV-listed with active exploitation. Public PoC available. Patch available from Microsoft. Attack requires user to mount malicious media (USB, VHD) but no authentication needed. High value for physical access attacks. |
| Exploit ScenarioDerived | An attacker creates a malicious FAT-formatted USB drive or VHD file with crafted directory entries that trigger the integer overflow in fastfat.sys. When a user inserts the USB drive or mounts the VHD (which may happen automatically via AutoPlay), the kernel driver processes the malicious structures, overflows a pool buffer, and the attacker achieves kernel-level code execution. This can also be delivered via email attachment (VHD file) or drive-by download. |
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Alert meAnalysisAIv1 – Mar 12, 2026
An integer overflow in the Windows Fast FAT Driver allows unauthenticated local code execution through crafted FAT filesystem images. KEV-listed with public PoC, this vulnerability (CVE-2025-24985) can be triggered by mounting a malicious USB drive or VHD file, making it a potent vector for physical access attacks and social engineering scenarios.
Earlier versions of this analysis (1)
Windows Fast FAT Driver contains an integer overflow (CWE-122) that leads to heap-based buffer overflow when parsing specially crafted FAT filesystem structures, enabling arbitrary code execution in kernel context.
RemediationAI
Apply Microsoft security update immediately. Disable AutoPlay for removable media. Consider blocking VHD file attachments at email gateway. Group Policy: restrict mounting of removable media on sensitive systems.
Affected ProductsAI
Microsoft Windows 10 (all versions) Microsoft Windows 11 Microsoft Windows Server 2016/2019/2022
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The Windows Fast FAT filesystem driver (fastfat.sys) fails to properly validate integer arithmetic when processing FAT directory entries. An attacker-controlled integer value overflows during size calculation, resulting in an undersized kernel pool allocation. Subsequent data copy overwrites adjacent kernel memory. Because filesystem drivers operate in kernel mode, successful exploitation yields SYSTEM-level code execution.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
Integer overflow or wraparound in Windows Fast FAT Driver allows an unauthorized attacker to execute code locally.
Executive ViewAI
Organizations using Integer overflow or wraparound in Windows Fast FAT Driver face notable risk from CVE-2025-24985, a heap-based buffer overflow vulnerability rated CVSS 7.8. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. This vulnerability is actively exploited in the wild (KEV-listed) and requires immediate remediation. A patch is available and should be applied as part of regular vulnerability management.
Apply vendor patch. If immediate patching is not feasible: (1) Enable ASLR and DEP where available; (2) Implement network segmentation; (3) Monitor for exploitation indicators.
Threat Intelligence Overview
NVD
CVE.org
CISA KEV
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
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GitHub PoC
Exploit-DB