CVE-2025-52938 is an out-of-bounds read vulnerability classified under CWE-125, affecting the dail8859 NotepadNext application, specifically versions through v0.11. The flaw resides in the lparser.c source file, within the singlevar() function, which lacks a necessary luaK_exp2anyregup call. This omission leads to a heap-based buffer over-read when the program compiles untrusted Lua code. Essentially, the vulnerability allows the application to read memory beyond the allocated buffer boundaries, potentially exposing sensitive data or causing application instability. The vulnerability is triggered locally (AV:L) without requiring authentication (PR:N) or user interaction (UI:N), but it requires that the attacker has the ability to compile or execute untrusted Lua scripts within NotepadNext. The CVSS v4.0 base score is 5.1, indicating a medium severity level, with partial impact on confidentiality, integrity, and availability. There are no known exploits in the wild at the time of publication, and no patches have been released yet. The vulnerability's scope is limited to systems running vulnerable versions of NotepadNext that process Lua code, and exploitation could lead to information disclosure or application crashes due to memory corruption.

For European organizations, the impact of CVE-2025-52938 depends largely on the adoption of NotepadNext in their environments, particularly where Lua scripting is used for automation or customization. Organizations that use NotepadNext to compile or run untrusted Lua code could face risks of sensitive data leakage or denial of service through application crashes. This is especially relevant for software development firms, research institutions, and enterprises relying on Lua scripting within their workflows. Although the vulnerability does not allow remote exploitation without local access, insider threats or compromised internal systems could leverage this flaw to escalate access or disrupt operations. The medium severity suggests moderate risk, but the absence of authentication and user interaction requirements lowers the barrier for exploitation in trusted environments. European organizations with stringent data protection regulations (e.g., GDPR) must consider the potential confidentiality impact, as out-of-bounds reads can expose memory contents that may include sensitive information. Additionally, critical infrastructure or sectors with high reliance on customized scripting tools could experience operational disruptions if exploited.

Given the lack of an official patch, European organizations should implement the following specific mitigations: 1) Restrict the use of NotepadNext to trusted users and environments, minimizing exposure to untrusted Lua scripts. 2) Employ application whitelisting and sandboxing techniques to isolate NotepadNext processes, preventing unauthorized code execution and limiting memory access scope. 3) Monitor and audit Lua script usage within NotepadNext to detect anomalous or unauthorized script compilation activities. 4) Temporarily disable or limit Lua code compilation features in NotepadNext where feasible until a patch is available. 5) Educate developers and users about the risks of processing untrusted Lua code and enforce strict code review policies. 6) Use endpoint detection and response (EDR) tools to identify unusual memory access patterns or crashes related to NotepadNext. 7) Maintain up-to-date backups and incident response plans to quickly recover from potential exploitation consequences. These targeted measures go beyond generic advice by focusing on controlling Lua script execution and isolating the vulnerable application component.