{
  "cveId": "CVE-2021-3517",
  "url": "https://patchblox.com/security/cve/CVE-2021-3517",
  "summary": "CVE-2021-3517 is fixed in 5 products on 1 platform, first by libxml2 2.9.4\u002Bdfsg1-6.1ubuntu1.4, released June 1, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "libxml2: The libxml2 library is a development toolbox providing the implementation of various XML standards.\n\nSecurity Fix(es)...",
  "description": "The libxml2 library is a development toolbox providing the implementation of various XML standards.\n\nSecurity Fix(es):\n\n* libxml2: Use-after-free in xmlEncodeEntitiesInternal() in entities.c (CVE-2021-3516)\n\n* libxml2: Heap-based buffer overflow in xmlEncodeEntitiesInternal() in entities.c (CVE-2021-3517)\n\n* libxml2: Use-after-free in xmlXIncludeDoProcess() in xinclude.c (CVE-2021-3518)\n\n* libxml2: NULL pointer dereference when post-validating mixed content parsed in recovery mode (CVE-2021-3537)\n\n* libxml2: Exponential entity expansion attack bypasses all existing protection mechanisms (CVE-2021-3541)\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.",
  "published": "2021-05-19T07:15:00Z",
  "severity": "Moderate",
  "cvss": 8.6,
  "epss": 0.16986,
  "epssPercentile": 0.97087,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libxml2",
      "release": "RHEL 8",
      "fixedVersion": "0:2.9.7-9.el8_4.2",
      "fix": "RHSA-2021:2569",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2569",
      "released": "2021-06-29T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "fix": "libxml2 2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libxml2-2.9.4-dfsg1-6.1ubuntu1.4",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "fix": "libxml2 2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2",
      "release": "ol 8",
      "fixedVersion": "0:2.9.7-9.0.1.el8_4.2",
      "fix": "ELSA-2021-2569",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2569",
      "released": "2021-07-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2-devel",
      "release": "RHEL 8",
      "fixedVersion": "0:2.9.7-9.el8_4.2",
      "fix": "RHSA-2021:2569",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2569",
      "released": "2021-06-29T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2-devel",
      "release": "ol 8",
      "fixedVersion": "0:2.9.7-9.0.1.el8_4.2",
      "fix": "ELSA-2021-2569",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2569",
      "released": "2021-07-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2-utils",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "fix": "libxml2-utils 2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libxml2-utils-2.9.4-dfsg1-6.1ubuntu1.4",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxml2-utils",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "fix": "libxml2-utils 2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxml2-utils-2.9.10-dfsg-5ubuntu0.20.04.1",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python-libxml2",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "fix": "python-libxml2 2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-python-libxml2-2.9.4-dfsg1-6.1ubuntu1.4",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python-libxml2",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "fix": "python-libxml2 2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-python-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-libxml2",
      "release": "RHEL 8",
      "fixedVersion": "0:2.9.7-9.el8_4.2",
      "fix": "RHSA-2021:2569",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2569",
      "released": "2021-06-29T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-libxml2",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "fix": "python3-libxml2 2.9.4\u002Bdfsg1-6.1ubuntu1.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-python3-libxml2-2.9.4-dfsg1-6.1ubuntu1.4",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-libxml2",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "fix": "python3-libxml2 2.9.10\u002Bdfsg-5ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-python3-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1",
      "released": "2021-06-01T07:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-libxml2",
      "release": "ol 8",
      "fixedVersion": "0:2.9.7-9.0.1.el8_4.2",
      "fix": "ELSA-2021-2569",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2569",
      "released": "2021-07-03T00:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}