The httpcon_check_session_url function in the Session Validation component of the EFM ipTIME A3004T router is designed to verify session integrity, but an implementation flaw fails to enforce proper authentication. An attacker can craft malformed HTTP requests that bypass this check, gaining unauthorized administrative control over the device. This flaw aligns with CWE‑287 (Improper Authentication) and enables attackers to execute any configuration, update, or firmware operations as if they were legitimate users.

The vulnerability is documented for the EFM ipTIME A3004T 14.19.0 firmware. No other versions are explicitly listed, so the scope is limited to that release until further notice.

With a CVSS score of 10, the flaw poses a critical risk. Although the EPSS score is unavailable, the public disclosure and the lack of an official vendor response suggest a high likelihood of exploitation. Attackers can target the device over the network, presumably via the management interface, by sending crafted requests to the httpcon_check_session_url endpoint. Because the vulnerability directly undermines authentication, it effectively turns the router into a remote command‑execution vector, and the flaw is not included in the CISA KEV catalog yet.