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CRITICAL

CVE-2026-89009

CVSS v3

9.1

CRITICAL

EPSS Score

1.0 %

exploit probability, as of 2026-09-25

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

WAVLINK WN535M1 and WN535M3 routers running firmware prior to M35M1_V250922 contain an unauthenticated arbitrary file write vulnerability that allows remote attackers to overwrite any file on the device by sending a crafted payload to the sync_server daemon on TCP port 13136. The daemon, which runs as root and requires no authentication, accepts a 100-byte filename field in its protocol header without path canonicalization, allowing attackers to supply an absolute path and write arbitrary conten

Technical details

Published
2026-09-11
Last Modified
2026-09-11

Frequently asked questions

What is CVE-2026-89009?

WAVLINK WN535M1 and WN535M3 routers running firmware prior to M35M1_V250922 contain an unauthenticated arbitrary file write vulnerability that allows remote attackers to overwrite any file on the device by sending a crafted payload to the sync_server daemon on TCP port 13136. The daemon, which runs as root and requires no authentication, accepts a 100-byte filename field in its protocol header without path canonicalization, allowing attackers to supply an absolute path and write arbitrary conten

Is CVE-2026-89009 actively exploited?

Active exploitation of CVE-2026-89009 has not been confirmed. Its EPSS score was 1.0% on 2026-09-25, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-89009?

CVE-2026-89009 has a CVSS v3 base score of 9.1 (CRITICAL severity).

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