CVE-2021-26087

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-17 · updated 2026-06-17
Weakness: CWE-79

Description

An improper neutralization of input during web page generation in FortiWLC version 8.6.0, version 8.5.3 and below, version 8.4.8 and below, version 8.3.3 web interface may allow both authenticated remote attackers and non-authenticated attackers in the same network as the appliance to perform a stored cross site scripting attack (XSS) via injecting malicious payloads in different locations.

Affected products

Fortinet FortiWLC: from 8.4.0 through 8.4.2; from 8.4.4 before 8.5.4; 8.3.3, 8.6.0 — fixed in 8.5.4

How to fix

Upgrade to a fixed version: Fortinet FortiWLC 8.5.4. Check the vendor advisory for mitigations.

References

https://fortiguard.fortinet.com/psirt/FG-IR-20-137

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