CVE-2026-40688Network attack vector

Authenticated root code execution via HTTP buffer overwrite

Published Apr 14, 2026 · Updated Apr 14, 2026

Out-of-bounds write in Fortinet FortiWeb allows remote authenticated users to execute arbitrary code via crafted HTTP requests. The cat_cgi_paths component fails to validate user-supplied HTTP data before writing past the end of an allocated buffer. High-privilege access is required; affected releases are 7.4.0 through 7.4.11, 7.6.0 through 7.6.6, and 8.0.0 through 8.0.3, and successful exploitation runs code as root.

CVSS severity7.2
High
EPSS probability6.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Fortinet FortiWeb allows remote authenticated users to execute arbitrary code via crafted HTTP requests. The cat_cgi_paths component fails to validate user-supplied HTTP data before writing past the end of an allocated buffer. High-privilege access is required; affected releases are 7.4.0 through 7.4.11, 7.6.0 through 7.6.6, and 8.0.0 through 8.0.3, and successful exploitation runs code as root.

The record

CVE
CVE-2026-40688
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
Fortinet
Product
FortiWeb
Classifications
CWE-787, T1210
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Apr 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2026Record 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=7.4.0 <=7.4.11
  2. Affected versionversion=7.6.0 <=7.6.6
  3. Affected versionversion=8.0.0 <=8.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Fortinet · FortiWebversion=7.4.0 <=7.4.11; version=7.6.0 <=7.6.6; version=8.0.0 <=8.0.3

Published CVSS scores

7.2Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
8.8Zero Day InitiativeCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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