CVE-2026-30923— libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
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I. Basic Information for CVE-2026-30923
Vulnerability Information
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Vulnerability Title
libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
跨界内存读
Source: NVD (National Vulnerability Database)
Vulnerability Title
Modsecurity 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Modsecurity是OWASP ModSecurity开源的一个Web流量安全处理库。 Modsecurity 3.0.15之前版本存在缓冲区错误漏洞，该漏洞源于使用t:hexDecode转换的规则检查包含单个字符的查询字符串参数时发生段错误，攻击者可以利用此漏洞崩溃工作进程导致拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| owasp-modsecurity | ModSecurity | < 3.0.15 | - |
II. Public POCs for CVE-2026-30923
| # | POC Description | Source Link | Shenlong Link |
|---|
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- Release v3.0.15 · owasp-modsecurity/ModSecurity · GitHubx_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-30923
IV. Related Vulnerabilities
Same product: ModSecurity
- CVE-2025-54571
ModSecurity's Insufficient Return Value Handling can Lead to - CVE-2025-52891
ModSecurity empty XML tag causes segmentation fault - CVE-2025-48866
ModSecurity has possible DoS vulnerability in sanitiseArg ac - CVE-2025-47947
ModSecurity Has Possible DoS Vulnerability - CVE-2025-27110
Libmodsecurity3 has possible bypass of encoded HTML entities
Same vendor: owasp-modsecurity
- CVE-2025-54571
ModSecurity's Insufficient Return Value Handling can Lead to - CVE-2025-52891
ModSecurity empty XML tag causes segmentation fault - CVE-2025-48866
ModSecurity has possible DoS vulnerability in sanitiseArg ac - CVE-2025-47947
ModSecurity Has Possible DoS Vulnerability - CVE-2025-27110
Libmodsecurity3 has possible bypass of encoded HTML entities
Same weakness: CWE-125
- CVE-2026-8177
XML::LibXML versions through 2.0210 for Perl read out-of-bou - CVE-2026-6104
Global buffer over-read in mb_convert_encoding() with attack - CVE-2026-7258
Out-of-bounds read in urldecode() on NetBSD - CVE-2026-8186
Open5GS NF client.c ogs_sbi_client_send_via_scp_or_sepp out- - CVE-2026-3508
ASUS System Control Interface 缓冲区错误漏洞
V. Comments for CVE-2026-30923
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