CVE-2026-27850

Improper verification in Linksys MR9600, Linksys MX4200

HIGH
7.5
CVSS Score
Published: February 25, 2026 at 04:58 PM UTC
Updated: June 17, 2026 at 10:27 AM UTC
2 products affected across 1 vendorMR9600MX4200

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

Due to an improperly configured firewall rule, the router will accept any connection on the WAN port with the source port 5222, exposing all services which are normally only accessible through the local network. This issue affects MR9600: 1.0.4.205530; MX4200: 1.0.13.210200.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

Third Party AdvisoryTechnical Description
Source: cverecord
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2025-014.txt

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED

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