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{"affected_release": [{"advisory": "RHSA-2026:43588", "cpe": "cpe:/a:redhat:hummingbird:1", "impact": "important", "package": "unbound-main-1.25.2-0.1.hum1", "product_name": "Red Hat Hardened Images", "release_date": "2026-07-22T00:00:00Z"}], "bugzilla": {"description": "unbound: Unbound: Denial of Service via malformed EDNS Report-Channel option", "id": "2503075", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2503075"}, "csaw": false, "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-805", "details": ["A flaw was found in Unbound. When the 'dns-error-reporting: yes' option is enabled, a remote attacker can send a specially crafted DNS response containing a malformed EDNS Report-Channel option from a delegated zone they control. This can lead to a stack variable overwrite, causing the Unbound daemon to terminate. This vulnerability results in a denial of service."], "name": "CVE-2026-55973", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-07-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-55973\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-55973\nhttps://nlnetlabs.nl/projects/unbound/download/#unbound-1-25-2"], "statement": "This Important denial of service flaw in Unbound occurs when the `dns-error-reporting` option is explicitly enabled, allowing a remote attacker to terminate the daemon with a crafted DNS response. While several Red Hat products are affected, many Red Hat Enterprise Linux and OpenShift Container Platform versions are not vulnerable as the affected code is not present.", "threat_severity": "Important"}

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