Untrusted Search Path in B&R APROL

Mitigation Strategies

The primary mitigation step is to update APROL to version R 4.4-01P5 or later, where this vulnerability is resolved.

As a workaround before applying the update, administrators should remove or replace all wildcard AliasMatch directives in the Apache configuration file with explicit aliases that reference specific APROL system and project names.

This reduces the risk of path traversal attacks that exploit the untrusted search path.

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Executive Summary

CVE-2026-6901 is an Untrusted Search Path vulnerability found in the webserver component of B&R Industrial Automation GmbH's APROL software versions prior to R 4.4-01P5.

This vulnerability allows authenticated local attackers to elevate their privileges by exploiting an untrusted search path in the system.

Essentially, attackers can gain higher access levels than intended by taking advantage of how the system searches for executable files or libraries, potentially compromising system integrity.

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Impact Analysis

This vulnerability can lead to privilege escalation, allowing an authenticated local attacker to gain higher access rights than they should have.

Such elevated privileges could compromise the integrity of the system, potentially allowing unauthorized actions or access to sensitive components.

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Detection Guidance

This vulnerability is related to an untrusted search path in the webserver component of APROL versions prior to R 4.4-01P5, which can be exploited by authenticated local attackers.

To detect the vulnerability, administrators should check the Apache configuration files for the presence of wildcard AliasMatch directives, which are a key factor in the vulnerability.

Suggested commands include searching for AliasMatch directives in Apache configuration files, for example:

• grep -r AliasMatch /etc/apache2/ or /etc/httpd/ (depending on your system) to find wildcard AliasMatch directives.
• Verify the APROL version installed to confirm if it is prior to R 4.4-01P5.

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