CVE-2025-24993: Microsoft Windows NTFS Heap-Based Buffer Overflow Vulnerability

CVE-2025-24993 is a heap-based buffer overflow in the Microsoft Windows New Technology File System (NTFS). An unauthorized local attacker can trigger it to execute code on the system. Because NTFS is core to Windows storage and file handling, successful abuse can give an attacker a foothold for further local privilege escalation or persistence on affected hosts. Confirm all version and patch details against the Microsoft advisory before acting.

This class of flaw matters for IT and security teams because local code execution on Windows endpoints or servers can turn limited access into full system compromise. CISA notes the vulnerability allows unauthorized local code execution and directs organizations to apply vendor mitigations or discontinue use if none are available.

How it works

The weakness is CWE-122: a heap-based buffer overflow. In NTFS, the operating system allocates a region of heap memory for processing certain file-system structures or operations. When the amount of data written exceeds the allocated buffer size without proper bounds checking, adjacent heap memory can be overwritten.

An attacker who already has local access (for example via a low-privilege account or a malicious file the user opens) can craft input that triggers the overflow. Overwriting heap metadata or function pointers can redirect execution flow to attacker-controlled code running in the context of the vulnerable process. Exact trigger conditions and required privileges are not detailed in the public summary; treat any local NTFS interaction as potentially relevant and verify the precise attack surface in the vendor advisory.

Am I affected? How to find it in your systems

The vulnerability affects Microsoft Windows systems that use NTFS, which is the default file system on virtually all modern Windows clients and servers. Inventory every Windows endpoint, server, and virtual machine in your environment.

• Use asset-management or endpoint-management tools (SCCM/ConfigMgr, Intune, WSUS, or equivalent) to list installed Windows versions and build numbers.
• Compare those builds against the fixed versions listed in the Microsoft security advisory for CVE-2025-24993; do not rely on generic version ranges.
• Check for systems that process untrusted or user-supplied files on NTFS volumes, including file servers, workstations used for document handling, and any hosts that mount external or network storage.
• Review local security logs and EDR telemetry for unusual process crashes, heap-corruption events, or unexpected code execution originating from system processes that interact with NTFS. Specific indicators of compromise are not provided in the public summary, so baseline normal NTFS activity and watch for anomalies after the advisory date.

Cloud-hosted Windows instances fall under the same inventory requirement; follow BOD 22-01 guidance where applicable.

How to remediate

Patch first. Apply the security update Microsoft released for CVE-2025-24993 according to the vendor instructions. Deploy through your normal Windows Update, WSUS, or Intune channels and verify installation with build-number checks.

• Prioritize internet-facing or multi-user systems, then high-value servers and privileged workstations.
• After patching, reboot as required by the update and confirm the fixed build is running.
• For this class of heap overflow, also enforce least-privilege accounts, keep endpoint detection and response agents current, and enable Windows Defender Exploit Guard or equivalent memory-protection features where available.
• If the product cannot be patched, CISA guidance is to discontinue use until mitigations are in place.

If you can't patch immediately

Reduce the attack surface until the vendor update can be applied.

• Segment systems that handle untrusted files so that a local compromise cannot easily reach domain controllers or sensitive data stores.
• Restrict local interactive logons and remove unnecessary local administrator rights.
• Use application-control policies (AppLocker, WDAC) to limit which binaries can execute from user-writable locations.
• Enable enhanced logging of process creation, file-system activity, and heap-related crashes; feed those logs into your SIEM or EDR for rapid detection.
• Where a host-based or network virtual-patching capability exists, apply a temporary signature or rule that blocks known trigger patterns once Microsoft or your security vendor publishes them. Confirm any such rule against the official advisory.
• If the affected feature can be disabled without breaking business function, do so until the patch is installed.

If your data may have been exposed

Actively exploited local code-execution vulnerabilities frequently lead to broader compromise and data theft. Known ransomware use of this CVE is not documented, yet any successful exploitation still warrants investigation of the host for persistence, credential theft, and lateral movement. Review endpoint and identity logs for the period of exposure, isolate affected machines, and rotate credentials that may have been present. You can also run a free exposure scan of your email addresses against known breach data sets to determine whether associated accounts appear in public breach collections.