Active debug code exists in Yamaha wireless LAN access point devices. If a logged-in user who knows how to use the debug function accesses the device's management page, this function can be enabled by performing specific operations. As a result, an arbitrary OS command may be executed and/or configuration settings of the device may be altered. Affected products and versions are as follows: WLX222 firmware Rev.24.00.03 and earlier, WLX413 firmware Rev.22.00.05 and earlier, WLX212 firmware Rev.21.00.12 and earlier, WLX313 firmware Rev.18.00.12 and earlier, and WLX202 firmware Rev.16.00.18 and earlier.
https://jvn.jp/en/vu/JVNVU99896362/
http://www.rtpro.yamaha.co.jp/RT/FAQ/Security/JVNVU99896362.html