{
  "threat_severity" : "Low",
  "public_date" : "2026-07-22T13:08:21Z",
  "bugzilla" : {
    "description" : "unbound: Unbound: Insecure DNS redirection via spoofed DNS answers",
    "id" : "2506132",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2506132"
  },
  "cvss3" : {
    "cvss3_base_score" : "3.7",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
    "status" : "verified"
  },
  "cwe" : "CWE-348",
  "details" : [ "In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer and can instead rewrite a BOGUS A/AAAA answer to point to an operator's configured IP. If the validator finds an expired or otherwise invalid RRSIG on an answer whose A record falls within a 'response-ip'/RPZ configuration, the answer is still rewritten and given a hard coded security level of INSECURE. This results in the client receiving an INSECURE NOERROR reply rewritten by the operator's configured IP. A malicious actor can exploit the possible poisonous effect by spoofing a BOGUS A/AAAA answer that falls inside the operator's configured subnet rewrites. Such DNSSEC protected answers are then insecurely redirected to the operator's configured target.", "A flaw in Unbound's respip module fails to verify the security status of incoming DNS answers when using response-ip rules or RPZ files. A remote attacker can exploit this by spoofing DNS answers to bypass DNSSEC protections and trigger unauthorized rewrites, redirecting clients to unintended locations." ],
  "statement" : "This vulnerability has a Low impact because it requires Unbound to be specifically configured with the 'respip' module and either a 'response-ip' redirect rule or an RPZ file. This non-default setup allows a remote attacker to spoof DNS answers, resulting in the insecure redirection of DNSSEC protected responses.",
  "affected_release" : [ {
    "product_name" : "Red Hat Hardened Images",
    "release_date" : "2026-07-22T00:00:00Z",
    "advisory" : "RHSA-2026:43588",
    "cpe" : "cpe:/a:redhat:hummingbird:1",
    "package" : "unbound-main-1.25.2-0.1.hum1"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "package_name" : "unbound",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Fix deferred",
    "package_name" : "unbound",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "unbound",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "unbound",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "unbound",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Fix deferred",
    "package_name" : "openshift/ose-rhel-coreos-8",
    "cpe" : "cpe:/a:redhat:openshift:4"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Fix deferred",
    "package_name" : "openshift/ose-rhel-coreos-9",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-50243\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-50243\nhttps://www.nlnetlabs.nl/downloads/unbound/CVE-2026-50243.txt" ],
  "name" : "CVE-2026-50243",
  "mitigation" : {
    "value" : "If IP-based rewriting is unused, leave module-config configured as \"validator iterator\" and do not configure response-ip redirects or RPZ-IP triggers. If these features are required, ensure validator is placed before respip in module-config and restrict upstream peer access to reduce exposure to spoofed DNS answers.",
    "lang" : "en:us"
  },
  "csaw" : false
}