An improper neutralization of input during web page generation vulnerability [CWE-79] in FortiOS 6.4.1 and below, 6.2.9 and below may allow…

published 2025-03-21 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-7234

cvss: 4.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

An improper neutralization of input during web page generation vulnerability [CWE-79] in FortiOS 6.4.1 and below, 6.2.9 and below may allow a remote unauthenticated attacker to either redirect users to malicious websites via a crafted "Host" header or to execute JavaScript code in the victim's browser context. This happens when the FortiGate has web filtering and category override enabled/configured.

Patch / fix

fixed in 1

fortinet fortios 6.2.10, 6.4.2

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 19 mo ago (2025-03-21)

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.7	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N/E:U/RL:X/RC:X
CNA	3.1	4.7	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

Fortinet FortiOS

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

Technology feeds

Fortinet rss critical rss

References

fortiguard.com /advisory/FG-IR-19-301
vendor-advisory

Sources

CVE List CVE-2019-16151
NVD CVE-2019-16151

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary