CVE-2026-4558Public exploitNetwork attack vector

Authenticated command execution via concatenated SmartConnect inputs

Published Mar 22, 2026 · Updated Mar 22, 2026

OS command injection in Linksys MR9600 2.0.6.206937 allows remote authenticated users to execute commands through the JNAP API. SmartConnect.lua's smartConnectConfigure function concatenates four request fields directly into an os.execute shell command without quoting or filtering. Exploitation requires router credentials and an unconfigured smart-mode state, after which commands execute in the firmware environment.

CVSS severity8.8
High
EPSS probability4.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in Linksys MR9600 2.0.6.206937 allows remote authenticated users to execute commands through the JNAP API. SmartConnect.lua's smartConnectConfigure function concatenates four request fields directly into an os.execute shell command without quoting or filtering. Exploitation requires router credentials and an unconfigured smart-mode state, after which commands execute in the firmware environment.

The record

CVE
CVE-2026-4558
Published
Mar 22, 2026
Updated
Mar 22, 2026
Vendor
Linksys
Product
MR9600
Classifications
CWE-77, CWE-78, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 22, 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=2.0.6.206937

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Linksys · MR9600version=2.0.6.206937

Published CVSS scores

9.0VulDBAV:N/AC:L/Au:S/C:C/I:C/A:C
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
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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

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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