CVE-2026-65680 in OneDrive
Summary
by MITRE • 08/11/2026
Improper link resolution before file access ('link following') in Microsoft OneDrive allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical privilege escalation flaw in Microsoft OneDrive that exploits improper link resolution mechanisms during file access operations. The vulnerability occurs when the application fails to properly validate symbolic links or hard links before executing file operations, creating opportunities for attackers to manipulate the file system traversal process. Such flaws typically arise from insufficient input validation and inadequate path resolution controls within the application's file handling subsystems.
The technical implementation of this vulnerability stems from Microsoft OneDrive's failure to properly sanitize file paths when resolving symbolic links during local file access operations. Attackers can exploit this weakness by creating malicious symbolic links that point to privileged system files or directories, then manipulate the OneDrive client to follow these links and execute unauthorized file operations. This type of vulnerability aligns with CWE-367 which specifically addresses Time-of-Check to Time-of-Use (TOCTOU) flaws, where the application's behavior changes between validation and execution phases.
From an operational perspective, this vulnerability allows an authorized attacker who already has user-level access to OneDrive to escalate their privileges locally on the system. The attack vector typically involves crafting malicious file structures or symbolic links that when processed by OneDrive will result in unintended file operations being performed with elevated privileges. This represents a significant security risk because it leverages legitimate application functionality to bypass normal access controls and potentially gain administrative privileges.
The impact of this vulnerability extends beyond simple privilege escalation as it can enable attackers to modify critical system files, install malicious software, or exfiltrate sensitive data. The flaw particularly affects Windows environments where OneDrive is actively running and has user permissions to create symbolic links. Security professionals should note that this vulnerability can be exploited through social engineering techniques where attackers convince users to open specific files or directories that contain malicious link structures. This makes the attack surface broader than typical privilege escalation vulnerabilities that require more direct system access.
Mitigation strategies should focus on implementing proper input validation and path resolution controls within OneDrive's file handling processes. Organizations should ensure that symbolic links are properly validated and that any link following operations include appropriate access control checks before file operations are executed. The recommended approach includes applying Microsoft security updates promptly, implementing restricted file permissions for OneDrive directories, and monitoring for unusual symbolic link creation patterns. This vulnerability specifically aligns with attack techniques documented in the MITRE ATT&CK framework under privilege escalation tactics where attackers leverage application flaws to gain elevated system access. Organizations should also consider implementing endpoint detection and response solutions that can identify suspicious symbolic link manipulation activities within OneDrive contexts.