by Kastro
Paper/Archive/CVE-2026-89009

CVE-2026-89009

WAVLINK Technology WN535M1 — WAVLINK WN535M1/WN535M3 Unauthenticated Arbitrary File Write via sync_server

EPSS 1%public exploitCVSS 9.1
critical.is priorityof 100
50
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 63.1.631 × 2012.6Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
WN535M1M35M1_V210223–CNA
WN535M3M35M1_V210223–CNA

Scores by source

VulnCheck (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
VulnCheck (CNA)8.8CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: partial

References

exploitgithub.com/camdsmith/wavlink-sync_server-rce/blob/main/README.mdpatchdocs.wavlink.xyz/Security_Advisory/WAVLINK-SA-2026-091301writeupvulncheck.com/advisories/wavlink-wn535m1-wn535m3-unauthenticated-arbitrary-file-write-via-sync-server