{
  "threat_severity" : "Moderate",
  "public_date" : "2026-03-25T13:34:14Z",
  "bugzilla" : {
    "description" : "bind: BIND: Unauthorized access due to use-after-return vulnerability in DNS query handling",
    "id" : "2451298",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2451298"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.4",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
    "status" : "verified"
  },
  "cwe" : "CWE-825",
  "details" : [ "A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.\nBIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.", "A flaw was found in BIND, specifically in the named server's handling of DNS queries signed with SIG(0). A remote attacker could exploit this use-after-return vulnerability by sending a specially-crafted DNS request. This could cause an Access Control List (ACL) to improperly match an IP address, potentially leading to unauthorized access to resources." ],
  "statement" : "This vulnerability has a Moderate impact. A use-after-return flaw in the `named` server of `bind9` allows a remote attacker to send a specially-crafted DNS request signed with SIG(0). This can lead to improper Access Control List (ACL) matching, potentially granting unauthorized access to resources. Red Hat Enterprise Linux 8 and 9 ship with BIND versions 9.16 and 9.18 respectively, which are not affected by this flaw. Red Hat Enterprise Linux 10 is affected.",
  "affected_release" : [ {
    "product_name" : "Red Hat Hardened Images",
    "release_date" : "2026-04-07T00:00:00Z",
    "advisory" : "RHSA-2026:6935",
    "cpe" : "cpe:/a:redhat:hummingbird:1",
    "package" : "bind-main-9.18.48-1.hum1"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "package_name" : "bind",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "bind",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "bind",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "bind",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "bind9.16",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "bind",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "bind9.18",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "dhcp",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Not affected",
    "package_name" : "rhcos",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-3591\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-3591\nhttps://downloads.isc.org/isc/bind9/9.20.21\nhttps://downloads.isc.org/isc/bind9/9.21.20\nhttps://kb.isc.org/docs/cve-2026-3591" ],
  "name" : "CVE-2026-3591",
  "mitigation" : {
    "value" : "Restrict network access to the `named` service to trusted clients and networks. Configure firewall rules to limit inbound connections to the DNS service port (UDP/TCP 53). For example, using `firewall-cmd --permanent --add-rich-rule='rule family=\"ipv4\" source address=\"<TRUSTED_IP_RANGE>\" port port=\"53\" protocol=\"udp\" accept'` and `firewall-cmd --reload`. This action may impact DNS resolution for clients outside the specified trusted networks. A service reload or restart may be required for changes to take effect.",
    "lang" : "en:us"
  },
  "csaw" : false
}