CVE-2021-26087 Cross-site scripting in FortiWLC

What is CVE-2021-26087?

CVE-2021-26087 is a medium-severity cross-site scripting vulnerability in Fortinet FortiWLC, published on 17 Mar 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-79

Which versions are affected by CVE-2021-26087?

It affects 1 product.

Products include Fortinet Fortiwlc.

How do I fix CVE-2021-26087?

No fix has been published for CVE-2021-26087 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-26087 being exploited?

There is no known exploitation of CVE-2021-26087 in the wild and no public exploit code.

Other vulnerabilities in Fortinet FortiWLC

• CVE-2017-17539 Hardcoded credentials in FortiWLC Critical 9.8
• CVE-2017-17540 Hardcoded credentials in FortiWLC Critical 9.8
• CVE-2016-7560 Hardcoded credentials in n/a Critical 9.8
• CVE-2016-8491 Hardcoded credentials in Fortinet FortiWLC Critical 9.1
• CVE-2021-42758 Privilege escalation in Fortinet FortiWLC High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-jqg7-j926-j8mj.