Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 uses the ecos_pw cookie for authentication, which contains Base64-encoded credential data combined with a static suffix. Because the encoding is reversible and lacks integrity protection, an attacker can reconstruct or forge a valid cookie value without proper authentication.

Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 stores administrative authentication material in the ecos_pw cookie using a reversible Base64-encoded format with a static suffix. An attacker who obtains or derives this cookie value can forge a valid administrative session and gain unauthorized access to the device.