CVE-2021-26112Network attack vector

Unauthenticated code execution via stack buffer overflows

Published Apr 6, 2022 · Updated Oct 25, 2024

Stack buffer overflows in Fortinet FortiWAN before 4.5.9 allow remote attackers to execute arbitrary code via crafted requests. Fortinet identifies the affected loci as network daemons and the command-line interpreter but has not disclosed the specific routines or unchecked copy operations. Network-daemon paths require no authentication; successful memory corruption can execute code in the appliance context, while CLI reachability depends on command access.

CVSS severity9.8
Critical
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflows in Fortinet FortiWAN before 4.5.9 allow remote attackers to execute arbitrary code via crafted requests. Fortinet identifies the affected loci as network daemons and the command-line interpreter but has not disclosed the specific routines or unchecked copy operations. Network-daemon paths require no authentication; successful memory corruption can execute code in the appliance context, while CLI reachability depends on command access.

The record

CVE
CVE-2021-26112
Published
Apr 6, 2022
Updated
Oct 25, 2024
Vendor
Fortinet
Product
FortiWAN
Classifications
CWE-121, CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 6, 2022CVE publishedPublication date reported by the CVE source.
  2. Oct 25, 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=FortiWAN before 4.5.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiWANversion=FortiWAN before 4.5.9

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1FortinetCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

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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