CVE-2023-54331 in Outline
Summary
by MITRE • 01/14/2026
Outline 1.6.0 contains an unquoted service path vulnerability that allows local attackers to potentially execute arbitrary code with elevated system privileges. Attackers can exploit the unquoted service path in the OutlineService executable to inject malicious code that will be executed with LocalSystem permissions.
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Analysis
by VulDB Data Team • 02/02/2026
The vulnerability identified as CVE-2023-54331 affects Outline 1.6.0, a popular secure networking solution that enables users to create and manage virtual private networks. This particular flaw manifests as an unquoted service path vulnerability within the OutlineService executable, representing a significant security weakness that can be exploited by local attackers to gain elevated system privileges. The vulnerability stems from improper handling of service paths during the installation process, creating an opportunity for malicious code injection that operates with the highest available system permissions.
The technical flaw occurs when the OutlineService executable is installed without proper quotation marks around the service path, allowing Windows to interpret the path incorrectly and potentially load malicious code from unintended locations. This vulnerability directly maps to CWE-428, which describes the improper resolution of a Windows service path, and falls under the broader category of path traversal and privilege escalation vulnerabilities. The unquoted service path creates a window of opportunity where an attacker can place a malicious executable in a directory that Windows will search before the legitimate service location, effectively hijacking the service execution flow.
Operational impact of this vulnerability is substantial as it enables local attackers to execute arbitrary code with LocalSystem privileges, which represents the highest level of system access available in Windows environments. This privilege escalation capability allows adversaries to bypass standard security controls, modify system files, install additional malware, and potentially establish persistent access to the compromised system. The vulnerability is particularly concerning because it requires no network connectivity for exploitation, making it a local privilege escalation vector that can be leveraged by attackers who already have limited user access to the system. The attack surface is further expanded by the fact that Outline is commonly deployed in enterprise environments where system administrators may not be aware of the service path configuration issues.
Mitigation strategies for CVE-2023-54331 should prioritize immediate remediation through official software updates from the vendor, which would address the unquoted service path configuration. System administrators should conduct thorough inventory checks to identify all instances of Outline 1.6.0 installations and verify service path configurations, ensuring proper quotation marks are used around executable paths during service registration. Additional defensive measures include implementing strict file system permissions, monitoring for unauthorized executable installations in service path directories, and conducting regular security audits of installed services. Organizations should also consider applying the ATT&CK framework's T1068 technique for privilege escalation by monitoring for suspicious service installations and ensuring that only trusted executables are present in service path locations. The vulnerability highlights the importance of proper service path configuration practices and underscores the need for regular security assessments of third-party applications to prevent exploitation of similar path traversal vulnerabilities that could lead to complete system compromise.