An authentication bypass flaw in the HTTP(S) management interface of Hirschmann HiOS and HiSecOS allows an unauthenticated attacker to craft requests that reveal the authentication status of a user who had previously logged in. The flaw stems from improper enforcement of authentication checks, mapping to CWE‑287. If exploited, the attacker can gain administrative privileges on the system, potentially compromising confidentiality, integrity, and availability of the device.

The vulnerability affects Belden Hirschmann HiOS and HiSecOS EAGLE products. Specific series impacted include RSP, RSPE, RSPS, RSPL, MSP, EES, EESX, GRS, OS, RED, and the EAGLE management platform. No version ranges are stated in the available data.

With a CVSS score of 9.3, the flaw is considered critical. Although EPSS data is not available, the absence of a known exploit in the KEV catalog does not mitigate the risk. The likely attack vector is a remote HTTP(S) request to the management interface, and the vulnerability can be triggered without credentials or prior user interaction, making it straightforward for attackers to obtain full administrative control.