Owasp: >> Modsecurity >> 2.9.11 Security Vulnerabilities
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.
CVSS Score
8.6
EPSS Score
0.005
Published
2026-07-10
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Libmodsecurity is one component of the ModSecurity v3 project. A segmentation fault occurs when a rule using the t:hexDecode transformation inspects a query string parameter containing a single character. An attacker can exploit this to crash worker processes, causing a denial of service. Service resumes once the attack stops as worker processes recover from the segfault. All versions before 3.0.15 of libModSecurity3 are affected. This has been patched in version 3.0.15.
CVSS Score
8.2
EPSS Score
0.004
Published
2026-05-05
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. In versions 2.9.11
and below, an attacker can override the HTTP response’s Content-Type, which could lead to several issues depending on the HTTP scenario. For example, we have demonstrated the potential for XSS and arbitrary script source code disclosure in the latest version of mod_security2. This issue is fixed in version 2.9.12.
CVSS Score
6.9
EPSS Score
0.003
Published
2025-08-06