WAVLINK WN535M1/WN535M3 up to M35M1_V250922 sync_server daemon filename path traversal

Summaryinfo

A vulnerability categorized as critical has been discovered in WAVLINK WN535M1 and WN535M3 up to M35M1_V250922. The affected element is an unknown function of the component sync_server daemon. Such manipulation of the argument filename leads to path traversal. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is uniquely identified as CVE-2026-89009. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in WAVLINK WN535M1 and WN535M3 up to M35M1_V250922. It has been rated as critical. Affected by this issue is an unknown functionality of the component sync_server daemon. The manipulation of the argument filename with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-89009 since 09/10/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/11/2026). The MITRE ATT&CK project declares the attack technique as T1006.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• WAVLINK

Name

• WN535M1
• WN535M3

Version

• M35M1_V250922

License

• commercial

Support

• end of life

CPE 2.3info

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CPE 2.2info

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