CVE-2026-4890

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{"bugzilla": {"description": "dnsmasq: NSEC bitmap parsing infinite loop", "id": "2458516", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458516"}, "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": "draft"}, "cwe": "CWE-835", "details": ["A denial of service vulnerability was discovered in dnsmasq's DNSSEC validation. When parsing NSEC and NSEC3 bitmap records, the window iteration logic fails to account for the 2-byte window header when advancing through the bitmap data. A specially crafted DNS response with a zero-length bitmap can cause an infinite loop, making dnsmasq unresponsive to all queries."], "name": "CVE-2026-4890", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Under investigation", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Under investigation", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Under investigation", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Under investigation", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Under investigation", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Under investigation", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-05-09T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-4890\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4890"], "statement": "This issue affects deployments with DNSSEC validation enabled (--dnssec). The flaw is reachable before RRSIG signature validation, meaning no valid DNSSEC signatures are required to trigger it. However, the primary impact is limited to denial of service.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "2.93"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "dnsmasq", "source": "cna", "vendor": "dnsmasq"}, "product": "dnsmasq", "vendor": "dnsmasq"}], "created": "2026-05-11T18:45:25.664290+00:00", "title": "dnsmasq DNSSEC Validation Denial of Service Vulnerability", "updated": "2026-10-25T19:15:16.922280+00:00", "vendors": ["dnsmasq", "dnsmasq$PRODUCT$dnsmasq"]}