Vulnerability from bitnami_vulndb
Published
2026-05-07 08:45
Modified
2026-05-07 09:12
Summary
libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
Details

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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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "modsecurity",
        "purl": "pkg:bitnami/modsecurity"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.0.15"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "type": "CVSS_V4"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-30923"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:trustwave:modsecurity:*:*:*:*:*:*:*:*"
    ],
    "severity": "High"
  },
  "details": "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.",
  "id": "BIT-modsecurity-2026-30923",
  "modified": "2026-05-07T09:12:02.780Z",
  "published": "2026-05-07T08:45:59.405Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.15"
    },
    {
      "type": "WEB",
      "url": "https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2g"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30923"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.