---
id: CVE-2026-89009
title: >-
  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 th…
summary: >-
  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 th…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'
cwe:
  - CWE-36
vendor: WAVLINK Technology
product: WN535M1
affected:
  - WN535M1 M35M1_V210223
  - WN535M3 M35M1_V210223
published: '2026-09-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T17:17:32.830'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89009'
references:
  - url: 'https://docs.wavlink.xyz/'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/camdsmith/wavlink-sync_server-rce/blob/main/README.md'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/wavlink-wn535m1-wn535m3-unauthenticated-arbitrary-file-write-via-sync-server
    label: disclosure@vulncheck.com
  - url: 'https://github.com/camdsmith/wavlink-sync_server-rce/blob/main/README.md'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-15T16:18:17.720897Z'
epss: 0.00676
epssPercentile: 0.50425
ingestedAt: '2026-09-11T16:45:47.862Z'
---

## Overview

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 content to overwrite startup scripts or credential stores to achieve persistent system compromise.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.