KEV Intelligence

Vulnerability report

Exploited in the wild High confidence Not in CISA KEV

CVE-2021-22122

Fortinet FortiWeb Cross-Site Scripting

Fortinet / Fortinet FortiWeb · FortiWeb 6.3.0 through 6.3.7 and version before 6.2.4

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Severity
CVSS 6.1 · Medium
Confidence
High
Exploit status
Exploited in the wild
EPSS
10.5%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-22122 is an unauthenticated vulnerability affecting Fortinet Fortinet FortiWeb. An improper neutralization of input during web page generation in FortiWeb GUI interface 6.3.0 through 6.3.7 and version before...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is high.

Who is affected?

Fortinet / Fortinet FortiWeb fortiweb 6.3.0 through 6.3.7 and version before 6.2.4.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Fortinet FortiWeb Cross-Site Scripting

An improper neutralization of input during web page generation in FortiWeb GUI interface 6.3.0 through 6.3.7 and version before 6.2.4 may allow an unauthenticated, remote attacker to perform a reflected cross site scripting attack (XSS) by injecting malicious payload in different vulnerable API end-points.

Vendor Product Affected Status
Fortinet Fortinet FortiWeb FortiWeb 6.3.0 through 6.3.7 and version before 6.2.4 Affected
Published
08 Feb 2021
Exploitation Reported
28 Dec 2025
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
Required

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 28 Dec 2025

Independent exploitation attestation added to the KEV Intelligence record.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
The Shadowserver First 2025-12-28 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-22122.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

10.5%

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE-79

All CVSS Scores

CVSS v3.1 6.1 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v2.0 4.3 Medium

AV:N/AC:M/Au:N/C:N/I:P/A:N

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

FortiWeb - Cross Site Scripting

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. Public PoC available

    Public proof-of-concept code published

  2. Added to KEV Intelligence KEV Feed

    High-confidence, third-party attested exploitation

  3. Nuclei template available

    Scanner coverage available

  4. CVE published

    Vulnerability disclosed publicly

  5. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-22122

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-22122",
  "confidence": "High",
  "cvss_score": 6.1,
  "cvss_estimated": false,
  "epss_score": 0.1052,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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