BAB TECHNOLOGIE GmbH eibPort V3 prior version 3.9.1 allow unauthenticated attackers access to /tmp path which contains some sensitive data (e.g. device serial number). Having those info, a possible loginId can be self-calculated in a brute force attack against BMX interface. This is usable and part of an attack chain to gain SSH root access.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-28911
• https://psytester.github.io/CVE-2021-28911