CVE-2026-4546 in Notepad2
Summary
by MITRE • 03/22/2026
A weakness has been identified in Flos Freeware Notepad2 4.2.25. This impacts an unknown function in the library TextShaping.dll. Executing a manipulation can lead to uncontrolled search path. The attack is restricted to local execution. The attack requires a high level of complexity. The exploitability is said to be difficult. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 06/04/2026
The vulnerability identified in Flos Freeware Notepad2 version 4.2.25 represents a significant security concern within the TextShaping.dll library component that governs text rendering functionality. This weakness manifests as an uncontrolled search path vulnerability, which occurs when an application fails to properly validate or control the paths it uses to locate and load dynamic link libraries. The specific function within TextShaping.dll that is affected remains unspecified, but the implications suggest a critical flaw in how the application handles library loading mechanisms. Such vulnerabilities are particularly dangerous because they can be exploited to load malicious code in place of legitimate system libraries, potentially leading to arbitrary code execution or privilege escalation. The vulnerability falls under the purview of CWE-428, which specifically addresses "Uncontrolled Search Path Element" and is classified as a path traversal or library loading vulnerability that can be exploited through manipulation of the search path.
The attack vector for this vulnerability is strictly limited to local execution, meaning that an attacker must already have access to the target system to exploit the flaw. This restriction significantly reduces the attack surface compared to remotely exploitable vulnerabilities, but it does not eliminate the risk entirely. The high complexity required for exploitation indicates that the vulnerability likely requires sophisticated techniques or specific conditions to be successfully leveraged. This complexity can include precise timing requirements, specific system configurations, or the need for additional preconditions that make the attack more challenging to execute. The difficulty level of exploitation aligns with ATT&CK technique T1059.001, which covers "Command and Scripting Interpreter" and suggests that even when exploitation is difficult, attackers may still attempt to leverage such vulnerabilities through advanced persistent threat campaigns or insider threats.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise the integrity and confidentiality of the system. When an attacker successfully exploits this uncontrolled search path, they may be able to inject malicious code that executes with the privileges of the affected application, which could range from standard user privileges to elevated system access depending on how Notepad2 is configured. The local execution requirement means that the vulnerability could be particularly concerning in environments where local access is not properly controlled or where users have the ability to manipulate system files. The fact that the vendor has not responded to early disclosure attempts raises serious concerns about the maintenance and security posture of this software, suggesting potential abandonment or lack of security awareness within the development team. This lack of vendor response also indicates that the software may be vulnerable to additional undiscovered issues, as the absence of timely patches or security updates leaves users exposed to potential exploitation. The vulnerability's classification as difficult to exploit does not diminish its importance, as even complex vulnerabilities can be leveraged by determined attackers who have the time and resources to develop sophisticated attack methods.
Mitigation strategies for this vulnerability should focus on immediate system hardening measures including restricting local file system access, implementing proper application whitelisting, and ensuring that all system components are regularly updated with the latest security patches. Users should be advised to avoid running Notepad2 with elevated privileges and to maintain strict control over system file modifications. The recommended approach includes implementing the principle of least privilege, where applications run with minimal necessary permissions, and deploying monitoring solutions that can detect anomalous library loading behaviors. Additionally, system administrators should consider implementing file integrity monitoring solutions that can detect unauthorized modifications to critical system libraries. The vulnerability serves as a reminder of the importance of proper library loading practices and the need for developers to implement secure coding practices that prevent uncontrolled search path exploitation. Organizations should also consider implementing security awareness training to help users understand the risks associated with running potentially vulnerable software and the importance of maintaining up-to-date security measures.