XSS in Fortinet Fortisandbox
CVE-2026-39812
A improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox PaaS 5.0.0 through 5.0.5, FortiSandbox PaaS 4.4.0 through 4.4.8, FortiSandbox PaaS 4.2 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (14.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Fortinet Fortisandbox — versions 5.0.0, 4.4.0, 4.2.1
- Fortinet Fortisandbox Cloud — versions 5.0.4, 5.0.5
- Fortinet Fortisandbox Paas — versions 5.0.0, 4.4.0, 4.2.1
Weakness classification (CWE)
References
- fortiguard.fortinet.com/psirt/FG-IR-26-110 (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-39812?
- CVE-2026-39812 is a medium-severity vulnerability in Fortinet Fortisandbox, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-04-14.
- How severe is CVE-2026-39812?
- Medium severity. CVSS v3 base score is 4.8 out of 10.