CVE-2026-30923
highpriority · track · 30EPSS 0.004 · 38 %ileDEEUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.6–8.2
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (8)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1308OWASP ModSecurity: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2026-04-28csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in OWASP ModSecurity ausnutzen, um einen Denial of Service Angriff durchzuführen.
- BIT-modsecurity-2026-30923libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings2026-05-07vendor · osvUS
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.
- BIT-modsecurity2-2026-30923libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings2026-05-07vendor · osvUS
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.
also known as (4)
Other names and identifiers for this entity.
- CNNVD-202605-756cnnvd
- EUVD-2026-27422enisa_euvd
- BIT-modsecurity-2026-30923osv
- GHSA-qrjc-3jpc-3h2gosv
sources
Which sources assert this record, and when.
references (6)
External citations — patches, advisories, analysis.
- https://modsecurity.org/Patchcnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2026-30923cnnvd
- https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.15enisa_euvd
- https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2genisa_euvd
- https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.15PatchProductnvd
- https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2gExploitVendor Advisorynvd
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