CVE-2019-16151Network attack vector

Browser script execution via unneutralized Host header

Published Mar 21, 2025 · Updated Mar 21, 2025

Cross-site scripting in Fortinet FortiOS 6.2.0 through 6.2.9 and 6.4.0 through 6.4.1 allows remote attackers to inject browser JavaScript. The web-filter category-override response embeds an untrusted Host header without sufficient neutralization, enabling redirection or script execution. No authentication is required, but web filtering and category override must be enabled and a victim must load the generated response.

CVSS severity4.7
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Fortinet FortiOS 6.2.0 through 6.2.9 and 6.4.0 through 6.4.1 allows remote attackers to inject browser JavaScript. The web-filter category-override response embeds an untrusted Host header without sufficient neutralization, enabling redirection or script execution. No authentication is required, but web filtering and category override must be enabled and a victim must load the generated response.

The record

CVE
CVE-2019-16151
Published
Mar 21, 2025
Updated
Mar 21, 2025
Vendor
Fortinet
Product
FortiOS
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.2.0 <=6.2.9
  2. Affected versionversion=6.4.0 <=6.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiOSversion=6.2.0 <=6.2.9; version=6.4.0 <=6.4.1

Published CVSS scores

4.7Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1189Drive-by Compromise

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

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Your stack

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