All have patches, so make sure you upgrade to a fixed version
Three critical flaws in Fortinet’s sandbox that allow remote attackers to bypass authentication, escalate privileges, and execute malicious code are under active exploitation, according to threat intelligence firm Defused. Fortinet patched two of the three flaws, CVE-2026-39813 and CVE-2026-39808, in April and the third, CVE-2026-25089 last week. All three bugs received 9.1 CVSS ratings, and, at the time, the vendor said that there were no reports of active exploitation.CVE-2026-39813 is a path traversal bug in the FortiSandbox JRPC API that allows an authentication bypass using specially crafted HTTP requests. It affects FortiSandbox 4.4.0 through 4.4.8 and 5.0.0 through 5.0.5. Patch to 4.4.9+ or 5.0.6+, depending on the branch, to fix the flaw. Fortinet security analyst Loic Pantano found this one.
CVE-2026-39808 is an OS command injection flaw in FortiSandbox that allows unauthenticated attackers to execute unauthorized code or commands via HTTP requests. It affects versions 4.4.0 through 4.4.8, and upgrading to FortiSandbox 4.4.9 or above patches the hole. Fortinet credited KPMG Spain researcher Samuel de Lucas Maroto with finding and reporting this bug.Finally, CVE-2026-25089 is another OS command vulnerability in FortiSandbox, FortiSandbox Cloud and FortiSandbox PaaS WEB UI that allows unauthenticated attackers to execute unauthorized commands using specifically crafted HTTP requests. FortiSandbox 4.4.0 through 4.4.8 and 5.0.0 through 5.0.5, FortiSandbox Cloud 5.0.4 through 5.0.5, and FortiSandbox PaaS 5.0.4 through 5.0.5 are vulnerable. Upgrading to a fixed version patches the hole.
