CVE-2021-26092Network attack vector

Reflected XSS via unsanitized error-page GET parameters

Published Feb 24, 2022 · Updated Oct 22, 2024

Reflected XSS in the SSL VPN web portal of Fortinet FortiOS and FortiProxy allows remote attackers to execute script via a crafted URL. The portal's error page returns malicious GET-parameter content without sanitizing it for HTML output, causing a victim's browser to execute the injected script. No authentication is required to prepare the request, but a victim must open the crafted link; the published impact is limited to script execution in the portal's web origin.

CVSS severity6.1
Medium
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Reflected XSS in the SSL VPN web portal of Fortinet FortiOS and FortiProxy allows remote attackers to execute script via a crafted URL. The portal's error page returns malicious GET-parameter content without sanitizing it for HTML output, causing a victim's browser to execute the injected script. No authentication is required to prepare the request, but a victim must open the crafted link; the published impact is limited to script execution in the portal's web origin.

The record

CVE
CVE-2021-26092
Published
Feb 24, 2022
Updated
Oct 22, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Oct 22, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.7Fortinet PSIRTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.6Fortinet PSIRTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N/E:F/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo