CVE-2026-4430

# Proof of Concept concept for CVE-2026-4430 # This script demonstrates how to modify an OOXML document to trigger the salt mismatch. import zipfile import shutil import os def create_malicious_ooxml(original_docx, output_docx): # Unzip the docx (which is a zip file) with zipfile.ZipFile(original_docx, 'r') as z: z.extractall('temp_docx') # Modify the encryption settings in [Content_Types].xml or a custom part # In a real exploit, specific XML parts related to encryption are altered # to contain mismatched salt values. # This is a placeholder for the specific XML manipulation logic. # Example: Simulating a mismatched salt parameter in a hypothetical configuration xml_path = os.path.join('temp_docx', 'docProps', 'app.xml') # (Actual PoC would target encryption specific parts like 'EncryptedPackage' or 'EncryptionInfo') # Repackage the docx with zipfile.ZipFile(output_docx, 'w') as z: for folder, subfolders, files in os.walk('temp_docx'): for file in files: file_path = os.path.join(folder, file) arcname = os.path.relpath(file_path, 'temp_docx') z.write(file_path, arcname) # Cleanup shutil.rmtree('temp_docx') print(f"Malicious document generated: {output_docx}") # Usage: # create_malicious_ooxml('normal.docx', 'exploit.docx')

{"cve": {"id": "CVE-2026-4430", "sourceIdentifier": "[email protected]", "published": "2026-05-07T08:16:00.967", "lastModified": "2026-05-08T16:48:01.610", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Out-of-bounds write vulnerability in The Document Foundation LibreOffice via crafted OOXML documents with mismatched encryption salt parameters.\n\nThis issue affects LibreOffice: from 26.2 before 26.2.3, from 25.8 before 25.8.7."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*", "versionStartIncluding": "25.8.0.0", "versionEndExcluding": "25.8.7.0", "matchCriteriaId": "CE758232-7A3D-4F2C-AA8B-59BA260F8A0A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*", "versionStartIncluding": "26.2.0.0", "versionEndExcluding": "26.2.3.0", "matchCriteriaId": "8828A33E-E5F2-4841-AEE7-555E52053313"}]}]}], "references": [{"url": "https://www.libreoffice.org/about-us/security/advisories/cve-2026-4430", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}