CVE-2026-49791 in Windows
Summary
by MITRE • 07/14/2026
Improper link resolution before file access ('link following') in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/14/2026
The vulnerability described represents a critical privilege escalation flaw within the Windows Routing and Remote Access Service that operates under the Common Weakness Enumeration framework as CWE-59. This issue specifically manifests in the improper resolution of symbolic links before file access operations, creating a path traversal condition that can be exploited by authenticated attackers with local system access. The RRAS service, which provides network routing capabilities including VPN services and remote access functionality, contains a design flaw where it fails to properly validate or resolve symbolic links during file operations, allowing malicious actors to manipulate file access paths.
The technical implementation of this vulnerability stems from the service's failure to properly canonicalize file paths before executing file operations, particularly when processing configuration files or accessing system resources. When an attacker with local access can create or manipulate symbolic links in strategic locations, they can redirect file access operations to arbitrary locations on the filesystem, potentially allowing them to read restricted files, modify system components, or escalate privileges beyond their initial access level. This flaw operates at the operating system level where the service performs file I/O operations without adequate validation of link resolution, making it particularly dangerous as it can be exploited even when the attacker lacks network-level privileges.
The operational impact of this vulnerability extends significantly beyond simple privilege escalation, as it provides attackers with potential access to sensitive routing configurations, authentication credentials stored in RRAS configuration files, and other system-critical resources that may contain information useful for further lateral movement or persistence. Attackers can leverage this flaw to compromise the integrity of the routing infrastructure, potentially redirecting network traffic or gaining unauthorized access to protected network segments. The vulnerability's exploitation requires only local authenticated access, making it particularly concerning for environments where local system accounts might be compromised through social engineering, credential theft, or other attack vectors.
Mitigation strategies should focus on immediate patch application from Microsoft as the primary defense mechanism, combined with operational security measures such as restricting local access to systems running RRAS services and implementing strict file permissions on routing configuration directories. System administrators should also consider disabling unnecessary RRAS functionality and implementing monitoring for suspicious file access patterns or symbolic link creation activities. The vulnerability's classification under ATT&CK technique T1068 suggests that attackers may leverage this privilege escalation as part of broader attack chains targeting network infrastructure, making it essential to address this issue promptly within the context of overall security posture management and compliance requirements.