{
  "threat_severity" : "Important",
  "public_date" : "2026-05-09T00:00:00Z",
  "bugzilla" : {
    "description" : "dnsmasq: DHCPv6 CLID buffer overflow in helper process",
    "id" : "2458518",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2458518"
  },
  "cvss3" : {
    "cvss3_base_score" : "8.8",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-122",
  "details" : [ "A heap buffer overflow was discovered in dnsmasq's DHCP script helper process. When processing DHCPv6 client identifiers (CLIDs), the helper hex-encodes the raw CLID bytes into a fixed-size buffer without length validation. Since DHCPv6 CLIDs can be up to 65,535 bytes, a crafted DHCPv6 packet can overflow the buffer with attacker-controlled content. The helper process runs with root privileges." ],
  "statement" : "Red Hat rates this as Important. The overflow occurs in a root-privileged helper process with attacker-controlled content, and the `--dhcp-script` option is enabled by default in libvirt virtual network configurations, which affects RHEL systems using virt-manager, virt-install, or cockpit-machines. Exploitation requires the attacker to send crafted DHCPv6 packets from within the virtual network, meaning a malicious VM guest could potentially exploit this for host-level code execution as root.",
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Will not fix",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "dnsmasq",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Affected",
    "package_name" : "rhcos",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-4892\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4892" ],
  "name" : "CVE-2026-4892",
  "csaw" : false
}