CVE-2025-29795 in Edge
Summary
by MITRE • 03/23/2025
Improper link resolution before file access ('link following') in Microsoft Edge (Chromium-based) allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/09/2025
The vulnerability identified as CVE-2025-29795 represents a critical privilege escalation flaw within Microsoft Edge's Chromium-based architecture that stems from improper link resolution before file access operations. This weakness specifically affects the browser's handling of symbolic links and hard links during file system interactions, creating a pathway for authorized but unprivileged attackers to gain elevated system privileges. The flaw exists in the browser's file access control mechanisms where it fails to properly validate or resolve symbolic links before executing file operations, potentially allowing malicious actors to redirect file access to privileged system locations.
From a technical perspective, this vulnerability manifests when Microsoft Edge processes file operations that involve symbolic links or hard links without sufficient validation of the target paths. The implementation appears to follow symbolic links without proper authorization checks, enabling an attacker to manipulate file access patterns to target system-critical files or directories. This behavior aligns with CWE-59, which describes improper link resolution before file access, and represents a classic privilege escalation vector through path traversal manipulation. The vulnerability is particularly concerning because it operates within the context of a legitimate browser application, making detection more challenging for traditional security monitoring systems.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with potential access to system resources that should remain restricted to administrative users. An attacker who can successfully exploit this flaw could potentially modify browser configuration files, access sensitive user data, or even install malicious components that persist across system sessions. The local nature of this privilege escalation means that the attacker must first establish a foothold on the target system, but once achieved, the vulnerability could enable full system compromise. This aligns with ATT&CK technique T1068, which covers local privilege escalation through improper link resolution, and T1548.002, which addresses abuse of Windows privileges.
Mitigation strategies for CVE-2025-29795 should prioritize immediate patch deployment from Microsoft, as this vulnerability requires core browser security updates to address the underlying link resolution implementation. Organizations should implement additional monitoring for unusual file access patterns, particularly those involving symbolic links or hard links within browser-related directories. Security teams should also consider restricting browser access to sensitive system locations through group policy configurations and enhanced file system permissions. The vulnerability demonstrates the importance of proper path validation in browser security contexts and highlights the need for comprehensive security testing of file access operations, especially those involving symbolic link resolution. Network segmentation and user access controls should be reviewed to minimize potential damage from successful exploitation, while regular security audits should verify that the browser's file access mechanisms properly validate all link targets before execution.