Fortinet FortiOS Vulnerabilities & Security Advisories
55 advisories tracked · FortiGuard PSIRT Advisories · 12 listed in the CISA Known Exploited Vulnerabilities catalog
Every row below is a published Fortinet advisory that VulniPulse classified as FortiOS, with the CVEs, affected and fixed releases and exploitation status the vendor stated. Severity mix: 7 critical, 6 high, 32 medium, 10 low.
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Source
FortiGuard PSIRT Advisories
Polled via the official FortiGuard PSIRT RSS feed (filestore.fortinet.com). PSIRT pages are fetched for new items to extract affected and fixed versions.
Latest Fortinet FortiOS advisories
High [CVE-2026-84393] improper validation of certificate with host mismatch vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6, FortiProxy 7.6.2 through 7.6.6 may allow attacker to information disclosure via <insert attack vector here>
A improper validation of certificate with host mismatch vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6, FortiProxy 7.6.2 through 7.6.6 may allow attacker to information disclosure
High [CVE-2026-84393] ZTNA Portal Improper Certificate Validation
CVSSv3 Score: 7.3 An improper certificate validation vulnerability [CWE-295] in FortiOS and FortiProxy Agentless ZTNA portal may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the communication channel between the ZTNA portal and the backend destination website. Revised on 2026-09-08 00:00:00
High [CVE-2025-53844] Out-of-bounds access in CAPWAP daemon
CVSSv3 Score: 8.3 An Out-Of-Bounds Write vulnerability [CWE-787] in FortiOS capwap daemon may allow an attacker controlling an authenticated FortiAP FortiExtender or FortiSwitch to gain execution privileges on the FortiGate device Revised on 2026-05-12 00:00:00
High [CVE-2026-22153] LDAP authentication bypass in Agentless VPN and FSSO
CVSSv3 Score: 7.5 An Authentication Bypass by Primary Weakness vulnerability [CWE-305] in FortiOS fnbamd may allow an unauthenticated attacker to bypass LDAP authentication of Agentless VPN or FSSO policy, under specific LDAP server configuration. Revised on 2026-07-04 00:00:00
High [CVE-2025-25249] heap-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0…
A heap-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiOS 6.4 all versions, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows attacker to execute unauthorized code or commands via specially crafted packets
High [CVE-2022-0778] Vulnerability in OpenSSL library
CVSSv3 Score: 7.5 A security advisory was released affecting the version of OpenSSL library used in some Fortinet products:CVE-2022-0778:The BN_mod_sqrt() function, which computes a modular square root, contains a bug that can cause it to loop forever for non-prime moduli. Internally this function is used when parsing certificates that contain elliptic curve public keys in compressed form or explicit elliptic curve parameters with a base point encoded in compressed form. It is possible to trigger the infinite loop by crafting a certificate that has invalid explicit curve parameters. Since certificate parsing happens prior to verification of the certificate signature, any process that parses an externally supplied certificate may thus be subject to a denial of service attack. The infinite loop can also be reached when parsing crafted private keys as they can contain explicit elliptic curve parameters. Affected products named by the advisory: FortiOS; FortiManager; FortiAnalyzer; FortiDeceptor; and 2 more.