XSS in Fortinet Fortisiem

CVE-2026-59838

A improper neutralization of script-related html tags in a web page (basic xss) vulnerability in Fortinet FortiSIEM 7.4.0, FortiSIEM 7.3.0 through 7.3.4, FortiSIEM 7.2.0 through 7.2.6, FortiSIEM 7.1 all versions, FortiSIEM 7.0 all versions, FortiSIEM 6.7 all versions, FortiSIEM 6.6 all versions, FortiSIEM 6.5 all versions, FortiSIEM 6.4 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.002 (14.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-59838: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-59838?
CVE-2026-59838 is a medium-severity vulnerability in Fortinet Fortisiem, classified under Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). CVSS score: 5.9/10. Published 2026-07-15.
How severe is CVE-2026-59838?
Medium severity. CVSS v3 base score is 5.9 out of 10.