Fortinet FortiOS: CVE-2023-42789: Out-of-bounds Write in captive portal

An out-of-bounds write vulnerability [CWE-787] and a Stack-based Buffer Overflow [CWE-121] in FortiOS & FortiProxy captive portal may allow an inside attacker who has access to captive portal to execute arbitrary code or commands via specially crafted HTTP requests.Workaround:Set a non form-based authentication scheme:config authentication schemeedit schemeset method methodnextendWhere <method> can be any of those :ntlm NTLM authentication.basic Basic HTTP authentication.digest Digest HTTP authentication.negotiate Negotiate authentication.fsso Fortinet Single Sign-On (FSSO) authentication.rsso RADIUS Single Sign-On (RSSO) authentication.ssh-publickey Public key based SSH authentication.cert Client certificate authentication.saml SAML authenticationNone of the enabled authentication schemes should be form-based.Please note that only devices with captive portal enabled are affected.