CVE-2026-89009 WAVLINK WN535M1/WN535M3 Unauthenticated Arbitrary File Write via sync_server
Remote attackers can overwrite arbitrary files on WAVLINK routers via the sync_server daemon to achieve persistent system compromise.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-89009?
CVE-2026-89009 is a high-severity path traversal vulnerability in WAVLINK Technology WN535M1, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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 content to overwrite startup scripts or credential stores to achieve persistent system compromise.
Weakness: CWE-36
Which versions are affected by CVE-2026-89009?
How do I fix CVE-2026-89009?
No fix has been published for CVE-2026-89009 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-89009 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89009 exists.
Sources
Also known as GHSA-pg3c-cqw3-4pgg.