{
  "cveId": "CVE-2021-42717",
  "url": "https://patchblox.com/security/cve/CVE-2021-42717",
  "summary": "CVE-2021-42717 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2021-42717, released December 7, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "modsecurity: ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects",
  "description": "ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.",
  "published": "2021-12-07T14:15:00Z",
  "severity": "high",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.03249,
  "epssPercentile": 0.88411,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libapache2-mod-security2",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.9.2-1ubuntu0.1~esm1",
      "fix": "libapache2-mod-security2 2.9.2-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libapache2-mod-security2-2.9.2-1ubuntu0.1-esm1",
      "released": "2023-01-20T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libapache2-mod-security2",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.9.3-1ubuntu0.1",
      "fix": "libapache2-mod-security2 2.9.3-1ubuntu0.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libapache2-mod-security2-2.9.3-1ubuntu0.1",
      "released": "2023-01-20T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "3.0.6-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "3.0.6-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity",
      "release": "Debian 14",
      "fixedVersion": "3.0.6-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity-apache",
      "release": "Debian 11.6 (bullseye)",
      "fixedVersion": "2.9.3-3\u002Bdeb11u1",
      "fix": "DSA-5023-1",
      "url": "https://patchblox.com/security/fix/linux/dsa-5023-1",
      "released": "2021-12-18T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity-apache",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "2.9.5-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity-apache",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "2.9.5-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    },
    {
      "platform": "linux",
      "product": "modsecurity-apache",
      "release": "Debian 14",
      "fixedVersion": "2.9.5-1",
      "fix": "DEBIAN-CVE-2021-42717",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-42717",
      "released": "2021-12-07T22:15:06Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}