{"schemaVersion":3,"id":"CVE-2026-30923","aliases":["UBUNTU-CVE-2026-30923","DEBIAN-CVE-2026-30923"],"status":"published","duplicateOf":null,"title":null,"description":"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. 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