CVE-2025-27733 in Windows
Summary
by MITRE • 04/08/2025
Out-of-bounds read in Windows NTFS allows an unauthorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 06/23/2026
This vulnerability represents a critical out-of-bounds read flaw within the Windows NTFS file system implementation that enables local privilege escalation attacks. The technical nature of this vulnerability stems from improper bounds checking during file system operations, specifically when processing certain NTFS structures or metadata. An attacker exploiting this flaw can manipulate file system data structures to cause the kernel to read memory beyond allocated boundaries, potentially allowing them to access privileged memory regions or extract sensitive information that could be leveraged for further exploitation.
The operational impact of this vulnerability is significant as it requires only local system access to exploit, making it particularly dangerous in environments where attackers have already gained user-level access. Once exploited, the out-of-bounds read can provide attackers with information disclosure capabilities that may reveal kernel memory contents, including potentially sensitive cryptographic keys, credential information, or other privileged data. This information can then be used to bypass security mechanisms and escalate privileges from standard user accounts to system-level administrator privileges.
From a cybersecurity perspective, this vulnerability aligns with CWE-129 which addresses insufficient bounds checking in input validation scenarios, and represents a classic example of how file system implementation flaws can lead to privilege escalation. The ATT&CK framework categorizes this under privilege escalation techniques where adversaries leverage software vulnerabilities to gain higher levels of access within a system. The vulnerability's exploitation typically involves crafting specific file system operations or manipulating existing files in ways that trigger the flawed memory access pattern, often through carefully constructed file attributes or metadata structures.
Mitigation strategies should focus on immediate patch deployment from Microsoft as the primary defense mechanism, alongside implementing additional security controls such as mandatory access controls and privilege separation. System administrators should also consider monitoring for unusual file system operations that might indicate exploitation attempts, while maintaining strict least privilege principles to minimize potential damage if exploitation occurs. The vulnerability demonstrates the critical importance of robust input validation in kernel-level code and highlights why file system implementations must rigorously validate all data structures before processing them at privileged levels.
This type of vulnerability represents a common class of flaws in complex operating system components where memory safety issues can be exploited to bypass security boundaries. The out-of-bounds read pattern has been documented in numerous similar cases throughout Windows history, emphasizing the need for continuous security auditing of kernel components and proper memory management practices during software development cycles. Organizations should also implement comprehensive vulnerability management programs that include regular patching schedules and system hardening measures to reduce exposure windows for such critical flaws.