CVE-2026-34026 is a CWE-23 relative path traversal vulnerability in Wertheim GmbH's SafeController Software for Vault Rooms (Safe Deposit Locker System), specifically in version 6.15.8328.28014. The vulnerability exists in the documentName parameter of the /safe/selfservice/openselfservicedocument endpoint, where the application uses attacker-controlled input to build file paths without proper validation. This allows an authenticated attacker, regardless of role or permission level, to access files outside the intended directory, potentially exposing sensitive application logs and binaries.

An attacker with any authenticated role can exploit this vulnerability to read arbitrary files accessible by the application. This may lead to disclosure of sensitive information such as application logs and binaries, which could facilitate further attacks or information leakage. The CVSS 4.0 base score is 7.1 (high severity), reflecting network attack vector, low attack complexity, no user interaction, and high confidentiality impact.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to the affected endpoint to trusted users only and monitor for suspicious activity. Implement input validation or filtering on the documentName parameter as a temporary mitigation if possible.