{
  "threat_severity" : "Moderate",
  "public_date" : "2026-03-20T19:59:00Z",
  "bugzilla" : {
    "description" : "glibc: glibc: Incorrect DNS response parsing via crafted DNS server response",
    "id" : "2449777",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2449777"
  },
  "cvss3" : {
    "cvss3_base_score" : "6.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
    "status" : "verified"
  },
  "cwe" : "CWE-1286",
  "details" : [ "Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.", "A flaw was found in glibc (the GNU C Library). When an application uses the `gethostbyaddr` or `gethostbyaddr_r` functions with a `nsswitch.conf` configuration that specifies glibc's DNS backend, a remote attacker can send a specially crafted DNS (Domain Name System) response. This crafted response can cause the application to incorrectly interpret a non-answer section of the DNS response as a valid answer, leading to potential misbehavior or incorrect information processing." ],
  "statement" : "This MODERATE impact flaw in glibc allows a remote attacker to send a specially crafted DNS response when an application uses `gethostbyaddr` or `gethostbyaddr_r` with glibc's DNS backend configured in `nsswitch.conf`. This can lead to incorrect interpretation of DNS responses. Red Hat Enterprise Linux versions 6, 7, 8, 9, and 10, as well as OpenShift Container Platform, are affected if applications are configured to use the vulnerable DNS backend.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "release_date" : "2026-05-19T00:00:00Z",
    "advisory" : "RHSA-2026:19061",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10.2",
    "package" : "glibc-0:2.39-121.el10_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2026-05-26T00:00:00Z",
    "advisory" : "RHSA-2026:20597",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "glibc-0:2.34-270.el9_8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2026-05-26T00:00:00Z",
    "advisory" : "RHSA-2026:20597",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "glibc-0:2.34-270.el9_8"
  }, {
    "product_name" : "Cost Management 4",
    "release_date" : "2026-06-22T00:00:00Z",
    "advisory" : "RHSA-2026:27998",
    "cpe" : "cpe:/a:redhat:cost_management:4::el9",
    "package" : "costmanagement/costmanagement-metrics-rhel9-operator:1780946239"
  }, {
    "product_name" : "Red Hat Hardened Images",
    "release_date" : "2026-04-09T00:00:00Z",
    "advisory" : "RHSA-2026:7316",
    "cpe" : "cpe:/a:redhat:hummingbird:1",
    "package" : "glibc-main-2.42-11.1.hum1"
  }, {
    "product_name" : "Red Hat Insights proxy 1.5",
    "release_date" : "2026-06-02T00:00:00Z",
    "advisory" : "RHSA-2026:22634",
    "cpe" : "cpe:/a:redhat:insights_proxy:1.5::el9",
    "package" : "insights-proxy/insights-proxy-container-rhel9:1780420428"
  }, {
    "product_name" : "Red Hat Update Infrastructure 5",
    "release_date" : "2026-06-16T00:00:00Z",
    "advisory" : "RHSA-2026:26319",
    "cpe" : "cpe:/a:redhat:rhui:5::el9",
    "package" : "rhui5/cds-rhel9:1781525684"
  }, {
    "product_name" : "Red Hat Update Infrastructure 5",
    "release_date" : "2026-06-16T00:00:00Z",
    "advisory" : "RHSA-2026:26319",
    "cpe" : "cpe:/a:redhat:rhui:5::el9",
    "package" : "rhui5/haproxy-rhel9:1781525671"
  }, {
    "product_name" : "Red Hat Update Infrastructure 5",
    "release_date" : "2026-06-16T00:00:00Z",
    "advisory" : "RHSA-2026:26319",
    "cpe" : "cpe:/a:redhat:rhui:5::el9",
    "package" : "rhui5/installer-rhel9:1781525693"
  }, {
    "product_name" : "Red Hat Update Infrastructure 5",
    "release_date" : "2026-06-16T00:00:00Z",
    "advisory" : "RHSA-2026:26319",
    "cpe" : "cpe:/a:redhat:rhui:5::el9",
    "package" : "rhui5/rhua-rhel9:1781525739"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Fix deferred",
    "package_name" : "compat-glibc",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Fix deferred",
    "package_name" : "glibc",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "compat-glibc",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "glibc",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "glibc",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Fix deferred",
    "package_name" : "rhcos",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-4437\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4437\nhttps://sourceware.org/bugzilla/show_bug.cgi?id=34014" ],
  "name" : "CVE-2026-4437",
  "mitigation" : {
    "value" : "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.",
    "lang" : "en:us"
  },
  "csaw" : false
}