CVE-2026-4566Public exploitNetwork attack vector

Authenticated code execution via unchecked strcpy

Published Mar 23, 2026 · Updated Mar 23, 2026

Stack-based buffer overflow in Belkin F9K1122 firmware 1.00.33 allows remote authenticated users to execute code via a crafted webpage parameter. The formWISP5G handler passes data derived from the webpage request parameter to strcpy without checking its length, overflowing the stack buffer reboot_msg. Reaching the management endpoint requires low-privileged authenticated access; successful exploitation can crash the device or run code with the web service's privileges.

CVSS severity8.8
High
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Belkin F9K1122 firmware 1.00.33 allows remote authenticated users to execute code via a crafted webpage parameter. The formWISP5G handler passes data derived from the webpage request parameter to strcpy without checking its length, overflowing the stack buffer reboot_msg. Reaching the management endpoint requires low-privileged authenticated access; successful exploitation can crash the device or run code with the web service's privileges.

The record

CVE
CVE-2026-4566
Published
Mar 23, 2026
Updated
Mar 23, 2026
Vendor
Belkin
Product
N600 Dual-Band Plug-in Wi‑Fi Range Extender
Classifications
CWE-119, CWE-121, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 23, 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=1.00.33

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Belkin · N600 Dual-Band Plug-in Wi‑Fi Range Extenderversion=1.00.33

Published CVSS scores

7.4VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
9.0VulDBAV:N/AC:L/Au:S/C:C/I:C/A:C
8.8VulDBCVSS: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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-121Stack-based Buffer Overflow
T1190Exploit Public-Facing Application

Public exploit references

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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