A buffer overflow vulnerability exists in the Local Firmware Upgrade Interface (httpupg.cgi) of Ruijie RG-ES205GC, RG-ES206GC-P, RG-ES208GC, RG-ES210GC-LP, and RG-ES210GS-P devices running ESW_1.0(1)B1P48. This vulnerability can be exploited remotely without authentication. Public exploit code is available, but no vendor response or patch has been provided.