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.

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Tue, 05 May 2026 22:00:00 +0000

Type Values Removed Values Added
First Time appeared Modsecurity
Modsecurity modsecurity
Vendors & Products Modsecurity
Modsecurity modsecurity

Tue, 05 May 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 05 May 2026 19:00:00 +0000

Type Values Removed Values Added
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. This has been patched in version 3.0.15.
Title libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
Weaknesses CWE-125
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-05T19:21:08.898Z

Reserved: 2026-03-07T16:40:05.884Z

Link: CVE-2026-30923

cve-icon Vulnrichment

Updated: 2026-05-05T19:20:39.690Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-05-05T19:16:21.567

Modified: 2026-05-05T20:16:56.060

Link: CVE-2026-30923

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-05T21:45:15Z

Weaknesses