CVE-2022-27491Network attack vector

Victim flooding via spoofed IPS block responses

Published Sep 6, 2022 · Updated Oct 22, 2024

Improper source verification in the Fortinet FortiOS IPS engine allows remote attackers to flood arbitrary victims with blocked-page HTML. The engine accepts crafted TCP requests without verifying their apparent source and sends its block response to the arbitrary victim address. Exploitation requires traffic to traverse an affected IPS engine and can consume the victim's bandwidth or connection-processing capacity without altering FortiOS data.

CVSS severity6.8
Medium
EPSS probability1.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper source verification in the Fortinet FortiOS IPS engine allows remote attackers to flood arbitrary victims with blocked-page HTML. The engine accepts crafted TCP requests without verifying their apparent source and sends its block response to the arbitrary victim address. Exploitation requires traffic to traverse an affected IPS engine and can consume the victim's bandwidth or connection-processing capacity without altering FortiOS data.

The record

CVE
CVE-2022-27491
Published
Sep 6, 2022
Updated
Oct 22, 2024
Vendor
Fortinet
Product
FortiOS
Classifications
T1498.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 6, 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

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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=FortiOS 7.2.0, 7.0.5, 7.0.4, 7.0.3, 7.0.2, 7.0.1, 7.0.0, 6.4.9, 6.4.8, 6.4.7, 6.4.6, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.10, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiOSversion=FortiOS 7.2.0, 7.0.5, 7.0.4, 7.0.3, 7.0.2, 7.0.1, 7.0.0, 6.4.9, 6.4.8, 6.4.7, 6.4.6, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.10, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.8Fortinet, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

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

T1498.002Reflection Amplification

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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