CVE-2026-52761

A flaw was found in ModSecurity, an open-source web application firewall (WAF). The t:utf8toUnicode transformation function, responsible for converting UTF-8 encoded characters to Unicode, generates incorrect output on i386 architectures. This vulnerability allows an attacker to bypass WAF rules, potentially enabling malicious requests to reach the protected application. The consequence is a moderate integrity loss due to the circumvention of security controls.

Conditions for Exploitation: Exploitation is strictly limited to 32-bit (i386) architectures, which reduces the likelihood of exploitation in typical deployments. Furthermore, it requires the ModSecurity configuration to actively use rules that rely on the affected transformation function.

Impact Limitations: The vulnerability functions solely as a WAF rule bypass and does not directly cause privilege escalation, data corruption, or arbitrary code execution on the host system. The actual impact depends entirely on whether the backend application being protected is vulnerable to the bypassed requests.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.