CVE-2026-42616 in NTFS-3G
Summary
by MITRE • 10/07/2026
In NTFS-3G before 2026.7.7, a heap buffer overflow exists in cat() in ntfscat.c that allows an attacker to corrupt heap memory in the ntfscat binary by crafting a malicious NTFS image. The overflow is triggered by reading a file.
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified as CVE-2026-XXXX represents a critical security flaw within the NTFS-3G open-source driver, specifically affecting versions prior to 2026.7.7. This issue manifests as a heap buffer overflow located in the cat function implemented in the ntfscat.c source file. The root cause of this vulnerability lies in insufficient boundary checks when processing data structures within an NTFS filesystem image. When the application attempts to read and display the contents of a file, it fails to validate that the size of the target data does not exceed the allocated heap memory buffer. This lack of rigorous input validation allows for arbitrary write operations beyond the bounds of the intended memory region, leading to potential corruption of adjacent heap metadata or other critical data structures stored in contiguous memory locations.
From an operational perspective, this vulnerability poses a severe risk to system integrity and availability. An attacker who can provide a maliciously crafted NTFS image file can trigger the overflow by instructing the ntfscat utility to read specific files contained within that image. The immediate consequence of exploiting this heap buffer overflow is memory corruption, which typically results in application crashes or segmentation faults, thereby causing a denial of service against any system relying on NTFS-3G for filesystem operations. However, given the nature of heap-based vulnerabilities, there is also a significant potential for remote code execution if an attacker can carefully control the data written to the overwritten memory regions. By manipulating adjacent heap chunks, it may be possible to overwrite function pointers or object vtables, allowing the injection and subsequent execution of arbitrary shellcode with the privileges of the user running the ntfscat binary.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) categories such as CWE-122: Heap-based Buffer Overflow and CWE-134: Use of Externally-Controlled Format String, although the primary classification remains heap overflow due to the memory corruption aspect. In terms of adversarial tactics, this flaw is relevant to MITRE ATT&CK technique T1059: Command and Scripting Interpreter if exploitation leads to code execution, or more broadly under initial access vectors where malicious files are used to compromise a system. The attack vector typically involves social engineering or supply chain compromise scenarios where an unsuspecting user mounts or accesses a specially crafted NTFS volume using the vulnerable version of NTFS-3G tools.
Mitigation strategies must focus on immediate patching and defensive configuration changes. Organizations should upgrade all instances of NTFS-3G to version 2026.7.7 or later, where this heap buffer overflow has been remediated through improved input validation and bounds checking in the cat function. In environments where upgrading is not immediately feasible, administrators should restrict access to ntfscat utilities by limiting execution permissions to trusted users only. Additionally, implementing strict file integrity monitoring can help detect attempts to mount or read suspicious NTFS images that may contain exploit payloads. Security teams should also consider deploying application whitelisting solutions to prevent the execution of unapproved binaries and ensure that any third-party filesystem drivers are sourced from verified vendors with rigorous security review processes in place.