How severe is CVE-2021-26087?

CVE-2021-26087 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-26087 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26087?

CVE-2021-26087 primarily affects Fortinet Fortiwlc. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26087?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2021-26087 have an EU (EUVD) identifier?

Yes. CVE-2021-26087 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-12908.

When was CVE-2021-26087 published?

CVE-2021-26087 was published on 2025-03-17 and last updated on 2026-06-17.

CVE-2021-26087

CVE-2021-26087 is a medium-severity vulnerability in Fortinet Fortiwlc with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-12908
Weakness: CWE-79
Affected product: Fortinet Fortiwlc
Published: 2025-03-17
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-26087?: 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.
How severe is CVE-2021-26087?: CVE-2021-26087 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-26087 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26087?: CVE-2021-26087 primarily affects Fortinet Fortiwlc. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26087?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-26087 have an EU (EUVD) identifier?: Yes. CVE-2021-26087 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-12908.
When was CVE-2021-26087 published?: CVE-2021-26087 was published on 2025-03-17 and last updated on 2026-06-17.

References

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

Affected products (3)

cpe:2.3:a:fortinet:fortiwlc:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiwlc:8.3.3:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiwlc:8.6.0:*:*:*:*:*:*:*

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