CVE-2026-4558: A flaw has been found in Linksys MR9600 2.0.6.206937

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HIGH 8.8MITIGATE

CVE-2026-4558 is a high-severity flaw (CVSS 8.8) affecting mr9600 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw has been found in Linksys MR9600 2.0.6.206937. Affected is the function smartConnectConfigure of the file SmartConnect.lua. Executing a manipulation of the argument configApSsid/configApPassphrase/srpLogin/srpPassword can lead to os command injection. The attack may be launched remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Why this priority

High severity
EPSS top 8%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	5.0% (top 8%)
CISA exploited list	No
Weakness	CWE-77, CWE-78
Published	2026-03-22
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: linksys

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-22 18:16 UTCPublished CVE record published
2026-06-17 10:56 UTCUpdated Record last modified

linksys mr9600 firmware MITIGATE

Affected: 2.0.6.206937

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.6.206937

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora ELN · perl-Encode · FIXED · 3.25-528.eln159 · FEDORA-2026-79991d0238 · source

sudo dnf upgrade --advisory=FEDORA-2026-79991d0238

Fedora 46 · fonttools · FIXED · 4.68.0-1.fc46 · FEDORA-2026-65d6c01c75 · source

sudo dnf upgrade --advisory=FEDORA-2026-65d6c01c75

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: www.linksys.com/

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-4558?

mr9600 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-4558 being exploited?

CVE-2026-4558 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-4558 affect?

CVE-2026-4558 affects mr9600 firmware. Severity is high (CVSS 8.8). A flaw has been found in Linksys MR9600 2.0.6.206937. Affected is the function smartConnectConfigure of the file SmartConnect.lua. Executing a manipulation of the argument configApSsid/configApPassphrase/srpLogin/srpPassword can lead to os

How urgent is CVE-2026-4558?

Priority 59/100. High severity; EPSS top 8%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2026-6992 HIGH 7.2 MITIGATE A vulnerability was identified in Linksys MR9600 2.0.6.206937
CVE-2026-25603 MEDIUM 6.6 MITIGATE MITIGATE Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Linksys MR9600

References

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