{
  "cveId": "CVE-2026-66046",
  "url": "https://patchblox.com/security/cve/CVE-2026-66046",
  "summary": "CVE-2026-66046 is fixed in 11 products on 1 platform, first by expat 2.2.5-3ubuntu0.9\u002Besm5, released August 20, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "Expat Denial of Service via storeAtts() Quadratic Complexity",
  "description": "Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType-\u003EdefaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options.",
  "published": "2026-08-18T08:16:00Z",
  "severity": "Important",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "cwe": "Inefficient Algorithmic Complexity",
  "epss": 0.00742,
  "epssPercentile": 0.54919,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66046",
  "fixes": [
    {
      "platform": "linux",
      "product": "MozillaFirefox",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "153.5.0-160000.1.1",
      "fix": "OPENSUSE-SU-2026:22139-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-22139-1",
      "released": "2026-11-07T00:47:19Z"
    },
    {
      "platform": "linux",
      "product": "MozillaFirefox",
      "release": "sles 15.6",
      "fixedVersion": "153.5.0-150400.157.16.1",
      "fix": "SUSE-SU-2026:4834-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4834-1",
      "released": "2026-11-07T00:42:08Z"
    },
    {
      "platform": "linux",
      "product": "MozillaFirefox",
      "release": "sles 15.7",
      "fixedVersion": "153.5.0-150400.157.16.1",
      "fix": "SUSE-SU-2026:4834-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4834-1",
      "released": "2026-11-07T00:42:08Z"
    },
    {
      "platform": "linux",
      "product": "MozillaFirefox",
      "release": "sles 16.0",
      "fixedVersion": "153.5.0-160000.1.1",
      "fix": "SUSE-SU-2026:24260-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-24260-1",
      "released": "2026-11-07T00:44:01Z"
    },
    {
      "platform": "linux",
      "product": "MozillaThunderbird",
      "release": "sles 15.7",
      "fixedVersion": "153.5.0-150400.13.9.1",
      "fix": "SUSE-SU-2026:4736-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4736-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "2.5.0-1\u002Bdeb12u4",
      "fix": "DEBIAN-CVE-2026-66046",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-66046",
      "released": "2026-09-05T01:57:10Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "2.9.0-1~deb13u1",
      "fix": "DEBIAN-CVE-2026-66046",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-66046",
      "released": "2026-09-05T01:57:10Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Debian 14",
      "fixedVersion": "2.8.4-1",
      "fix": "DEBIAN-CVE-2026-66046",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-66046",
      "released": "2026-09-05T01:57:10Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "RHEL 10",
      "fixedVersion": "2.7.3-1.el10_2.5",
      "fix": "RHSA-2026:74001",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2026-74001",
      "released": "2026-10-01T20:54:27Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "RHEL 8",
      "fixedVersion": "0:2.5.0-4.el8_10",
      "fix": "RHSA-2026:72448",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2026-72448",
      "released": "2026-09-29T20:27:12Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "RHEL 9",
      "fixedVersion": "0:2.5.0-6.el9_8.5",
      "fix": "RHSA-2026:72663",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2026-72663",
      "released": "2026-09-29T20:28:38Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.2.5-3ubuntu0.9\u002Besm5",
      "fix": "expat 2.2.5-3ubuntu0.9\u002Besm5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-expat-2.2.5-3ubuntu0.9-esm5",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.2.9-1ubuntu0.8\u002Besm3",
      "fix": "expat 2.2.9-1ubuntu0.8\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-expat-2.2.9-1ubuntu0.8-esm3",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "2.4.7-1ubuntu0.9",
      "fix": "expat 2.4.7-1ubuntu0.9",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-expat-2.4.7-1ubuntu0.9",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "2.6.1-2ubuntu0.6",
      "fix": "expat 2.6.1-2ubuntu0.6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-expat-2.6.1-2ubuntu0.6",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "2.7.4-1ubuntu0.2",
      "fix": "expat 2.7.4-1ubuntu0.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-expat-2.7.4-1ubuntu0.2",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "almalinux 10",
      "fixedVersion": "2.7.3-1.el10_2.5",
      "fix": "ALSA-2026:74001",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-74001",
      "released": "2026-09-30T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "almalinux 8",
      "fixedVersion": "2.5.0-4.el8_10",
      "fix": "ALSA-2026:72448",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-72448",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "almalinux 9",
      "fixedVersion": "2.5.0-6.el9_8.5",
      "fix": "ALSA-2026:72663",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-72663",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "amzn 2023",
      "fixedVersion": "2.8.3-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2157",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2157",
      "released": "2026-09-14T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "ol 10",
      "fixedVersion": "0:2.7.3-1.el10_2.5",
      "fix": "ELSA-2026-74001",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-74001",
      "released": "2026-10-01T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "ol 8",
      "fixedVersion": "0:2.5.0-4.el8_10",
      "fix": "ELSA-2026-72448",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-72448",
      "released": "2026-09-29T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "ol 9",
      "fixedVersion": "0:2.5.0-6.el9_8.5",
      "fix": "ELSA-2026-72663",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-72663",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "2.8.4-160000.1.1",
      "fix": "OPENSUSE-SU-2026:21945-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-21945-1",
      "released": "2026-09-24T07:03:56Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "rocky 10",
      "fixedVersion": "0:2.7.3-1.el10_2.5",
      "fix": "RLSA-2026:74001",
      "url": "https://patchblox.com/security/fix/linux/rlsa-2026-74001",
      "released": "2026-10-01T12:08:49Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "rocky 8",
      "fixedVersion": "0:2.5.0-4.el8_10",
      "fix": "RLSA-2026:72448",
      "url": "https://patchblox.com/security/fix/linux/rlsa-2026-72448",
      "released": "2026-09-29T06:01:09Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "rocky 9",
      "fixedVersion": "0:2.5.0-6.el9_8.5",
      "fix": "RLSA-2026:72663",
      "url": "https://patchblox.com/security/fix/linux/rlsa-2026-72663",
      "released": "2026-09-30T12:05:19Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "sles 15.6",
      "fixedVersion": "2.8.5-150400.3.40.1",
      "fix": "SUSE-SU-2026:4623-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4623-1",
      "released": "2026-11-07T00:41:11Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "sles 15.7",
      "fixedVersion": "2.8.5-150700.3.15.1",
      "fix": "SUSE-SU-2026:4619-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4619-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "expat",
      "release": "sles 16.0",
      "fixedVersion": "2.8.4-160000.1.1",
      "fix": "SUSE-SU-2026:23912-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-23912-1",
      "released": "2026-09-24T07:07:13Z"
    },
    {
      "platform": "linux",
      "product": "expat-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "2.8.3-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2157",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2157",
      "released": "2026-09-14T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "2.8.3-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2157",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2157",
      "released": "2026-09-14T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "RHEL 8",
      "fixedVersion": "0:2.5.0-4.el8_10",
      "fix": "RHSA-2026:72448",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2026-72448",
      "released": "2026-09-29T20:27:12Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "RHEL 9",
      "fixedVersion": "0:2.5.0-6.el9_8.5",
      "fix": "RHSA-2026:72663",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2026-72663",
      "released": "2026-09-29T20:28:38Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "almalinux 10",
      "fixedVersion": "2.7.3-1.el10_2.5",
      "fix": "ALSA-2026:74001",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-74001",
      "released": "2026-09-30T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "almalinux 8",
      "fixedVersion": "2.5.0-4.el8_10",
      "fix": "ALSA-2026:72448",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-72448",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "almalinux 9",
      "fixedVersion": "2.5.0-6.el9_8.5",
      "fix": "ALSA-2026:72663",
      "url": "https://patchblox.com/security/fix/linux/alsa-2026-72663",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "amzn 2023",
      "fixedVersion": "2.8.3-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2157",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2157",
      "released": "2026-09-14T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "ol 10",
      "fixedVersion": "0:2.7.3-1.el10_2.5",
      "fix": "ELSA-2026-74001",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-74001",
      "released": "2026-10-01T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "ol 8",
      "fixedVersion": "0:2.5.0-4.el8_10",
      "fix": "ELSA-2026-72448",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-72448",
      "released": "2026-09-29T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-devel",
      "release": "ol 9",
      "fixedVersion": "0:2.5.0-6.el9_8.5",
      "fix": "ELSA-2026-72663",
      "url": "https://patchblox.com/security/fix/linux/elsa-2026-72663",
      "released": "2026-09-28T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "expat-static",
      "release": "amzn 2023",
      "fixedVersion": "2.8.3-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2157",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2157",
      "released": "2026-09-14T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "amzn 2023",
      "fixedVersion": "140.14.0-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2105",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2105",
      "released": "2026-08-31T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "140.14.0-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2105",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2105",
      "released": "2026-08-31T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "140.14.0-1.amzn2023.0.1",
      "fix": "ALAS2023-2026-2105",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2105",
      "released": "2026-08-31T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libexpat1",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "2.2.5-3ubuntu0.9\u002Besm5",
      "fix": "libexpat1 2.2.5-3ubuntu0.9\u002Besm5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libexpat1-2.2.5-3ubuntu0.9-esm5",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "libexpat1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "2.2.9-1ubuntu0.8\u002Besm3",
      "fix": "libexpat1 2.2.9-1ubuntu0.8\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libexpat1-2.2.9-1ubuntu0.8-esm3",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "libexpat1",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "2.4.7-1ubuntu0.9",
      "fix": "libexpat1 2.4.7-1ubuntu0.9",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-libexpat1-2.4.7-1ubuntu0.9",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "libexpat1",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "2.6.1-2ubuntu0.6",
      "fix": "libexpat1 2.6.1-2ubuntu0.6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-libexpat1-2.6.1-2ubuntu0.6",
      "released": "2026-08-20T11:16:00Z"
    },
    {
      "platform": "linux",
      "product": "libexpat1",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "2.7.4-1ubuntu0.2",
      "fix": "libexpat1 2.7.4-1ubuntu0.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-libexpat1-2.7.4-1ubuntu0.2",
      "released": "2026-08-20T11:16:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}