EXECUTIVE SUMMARY:
Multiple security vulnerabilities have been identified in OWASP ModSecurity versions. These issues involve web application firewall bypass flaws that allow attackers to circumvent security rules and deliver malicious payloads to backend applications. Because ModSecurity is widely deployed across Apache, Nginx, and IIS platforms, these vulnerabilities pose a significant business risk by undermining a critical layer of defense. Successful exploitation could enable threat actors to evade detection, potentially leading to unauthorized data access or system compromise while operators remain unaware of the intrusion due to silent rule failures.[/subscribe_to_unlock_form]
EXECUTIVE SUMMARY:
Multiple security vulnerabilities have been identified in OWASP ModSecurity versions. These issues involve web application firewall bypass flaws that allow attackers to circumvent security rules and deliver malicious payloads to backend applications. Because ModSecurity is widely deployed across Apache, Nginx, and IIS platforms, these vulnerabilities pose a significant business risk by undermining a critical layer of defense. Successful exploitation could enable threat actors to evade detection, potentially leading to unauthorized data access or system compromise while operators remain unaware of the intrusion due to silent rule failures.[emaillocker id="1283"]
CVE-2026-52747 with a CVSS score of 8.6 – This multipart parser bypass occurs because the parser removes embedded line breaks from field values, allowing payloads hidden by line breaks to reach backend applications undetected by the firewall.
CVE-2026-52761 with a CVSS score of 5.8 – This vulnerability allows rule evasion on i386 architectures because the t:utf8toUnicode transformation returns incorrect output, enabling attackers to bypass security checks on legacy systems.
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REFERENCES:
The following reports contain further technical details:
https://securityonline.info/modsecurity-vulnerabilities-cve-2026-52747/