{
  "threat_severity" : "Important",
  "public_date" : "2026-05-09T00:00:00Z",
  "bugzilla" : {
    "description" : "dnsmasq: NSEC bitmap parsing infinite loop",
    "id" : "2458516",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2458516"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-835",
  "details" : [ "A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.", "A denial of service vulnerability was discovered in dnsmasq's DNSSEC validation. When parsing NSEC and NSEC3 bitmap records, the window iteration logic fails to account for the 2-byte window header when advancing through the bitmap data. A specially crafted DNS response with a zero-length bitmap can cause an infinite loop, making dnsmasq unresponsive to all queries." ],
  "statement" : "This issue affects deployments with DNSSEC validation enabled (--dnssec). The flaw is reachable before RRSIG signature validation, meaning no valid DNSSEC signatures are required to trigger it. However, the primary impact is limited to denial of service.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "release_date" : "2026-05-19T00:00:00Z",
    "advisory" : "RHSA-2026:19158",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10.2",
    "package" : "dnsmasq-0:2.90-7.el10_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2026-05-19T00:00:00Z",
    "advisory" : "RHSA-2026:19373",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "dnsmasq-0:2.85-18.el9_8.1"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Under investigation",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Under investigation",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Under investigation",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Under investigation",
    "package_name" : "rhcos",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-4890\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4890\nhttps://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html" ],
  "name" : "CVE-2026-4890",
  "csaw" : false
}