Vulnerability Details CVE-2026-30923
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 18.0%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-30923
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cpe:2.3:a:owasp:modsecurity:2.0.0
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cpe:2.3:a:owasp:modsecurity:2.0.1
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cpe:2.3:a:owasp:modsecurity:2.0.2
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cpe:2.3:a:owasp:modsecurity:2.0.3
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cpe:2.3:a:owasp:modsecurity:2.0.4
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cpe:2.3:a:owasp:modsecurity:2.1.0
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cpe:2.3:a:owasp:modsecurity:2.1.1
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cpe:2.3:a:owasp:modsecurity:2.1.2
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cpe:2.3:a:owasp:modsecurity:2.1.3
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cpe:2.3:a:owasp:modsecurity:2.1.4
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cpe:2.3:a:owasp:modsecurity:2.1.5
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cpe:2.3:a:owasp:modsecurity:2.1.6
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cpe:2.3:a:owasp:modsecurity:2.1.7
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cpe:2.3:a:owasp:modsecurity:2.2.0
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cpe:2.3:a:owasp:modsecurity:2.5.0
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cpe:2.3:a:owasp:modsecurity:2.5.1
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cpe:2.3:a:owasp:modsecurity:2.5.10
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cpe:2.3:a:owasp:modsecurity:2.5.11
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cpe:2.3:a:owasp:modsecurity:2.5.12
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cpe:2.3:a:owasp:modsecurity:2.5.13
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cpe:2.3:a:owasp:modsecurity:2.5.2
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cpe:2.3:a:owasp:modsecurity:2.5.3
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cpe:2.3:a:owasp:modsecurity:2.5.4
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cpe:2.3:a:owasp:modsecurity:2.5.5
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cpe:2.3:a:owasp:modsecurity:2.5.6
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cpe:2.3:a:owasp:modsecurity:2.5.7
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cpe:2.3:a:owasp:modsecurity:2.5.8
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cpe:2.3:a:owasp:modsecurity:2.5.9
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cpe:2.3:a:owasp:modsecurity:2.6.0
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cpe:2.3:a:owasp:modsecurity:2.6.1
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cpe:2.3:a:owasp:modsecurity:2.6.2
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cpe:2.3:a:owasp:modsecurity:2.6.3
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cpe:2.3:a:owasp:modsecurity:2.6.4
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cpe:2.3:a:owasp:modsecurity:2.6.5
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cpe:2.3:a:owasp:modsecurity:2.6.6
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cpe:2.3:a:owasp:modsecurity:2.6.7
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cpe:2.3:a:owasp:modsecurity:2.6.8
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cpe:2.3:a:owasp:modsecurity:2.7.0
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cpe:2.3:a:owasp:modsecurity:2.7.1
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cpe:2.3:a:owasp:modsecurity:2.7.2
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cpe:2.3:a:owasp:modsecurity:2.7.3
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cpe:2.3:a:owasp:modsecurity:2.7.4
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cpe:2.3:a:owasp:modsecurity:2.7.5
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cpe:2.3:a:owasp:modsecurity:2.7.6
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cpe:2.3:a:owasp:modsecurity:2.7.7
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cpe:2.3:a:owasp:modsecurity:2.8.0
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cpe:2.3:a:owasp:modsecurity:2.9.0
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cpe:2.3:a:owasp:modsecurity:2.9.1
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cpe:2.3:a:owasp:modsecurity:2.9.10
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cpe:2.3:a:owasp:modsecurity:2.9.11
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cpe:2.3:a:owasp:modsecurity:2.9.12
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cpe:2.3:a:owasp:modsecurity:2.9.2
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cpe:2.3:a:owasp:modsecurity:2.9.3
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cpe:2.3:a:owasp:modsecurity:2.9.4
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cpe:2.3:a:owasp:modsecurity:2.9.5
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cpe:2.3:a:owasp:modsecurity:2.9.6
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cpe:2.3:a:owasp:modsecurity:2.9.7
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cpe:2.3:a:owasp:modsecurity:2.9.8
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cpe:2.3:a:owasp:modsecurity:2.9.9
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cpe:2.3:a:owasp:modsecurity:3.0.0
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cpe:2.3:a:owasp:modsecurity:3.0.1
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cpe:2.3:a:owasp:modsecurity:3.0.10
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cpe:2.3:a:owasp:modsecurity:3.0.11
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cpe:2.3:a:owasp:modsecurity:3.0.12
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cpe:2.3:a:owasp:modsecurity:3.0.13
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cpe:2.3:a:owasp:modsecurity:3.0.14
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cpe:2.3:a:owasp:modsecurity:3.0.2
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cpe:2.3:a:owasp:modsecurity:3.0.3
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cpe:2.3:a:owasp:modsecurity:3.0.4
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cpe:2.3:a:owasp:modsecurity:3.0.5
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cpe:2.3:a:owasp:modsecurity:3.0.6
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cpe:2.3:a:owasp:modsecurity:3.0.8
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cpe:2.3:a:owasp:modsecurity:3.0.9