CVE-2026-89009
CriticalCVSS 9.1Summary
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.
Risk Assessment
Allows a remote attacker to overwrite arbitrary files, including startup scripts and credentials, leading to persistent device compromise.
Recommendation
Update the firmware of WAVLINK WN535M1 and WN535M3 routers to version M35M1_V250922 or later.
Other vulnerabilities in WAVLINK WN535M1/WN535M3
Original NVD description (English source)
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.