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{"bugzilla": {"description": "unbound: Unbound: Denial of Service due to incorrect client reply accounting with specific serve-expired configuration", "id": "2506142", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2506142"}, "csaw": false, "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:N/A:L", "status": "draft"}, "cwe": "CWE-772", "details": ["A Denial of Service (DoS) flaw exists in Unbound under specific serve-expired and discard-timeout configurations. By sending crafted queries, a remote attacker can exhaust an internal counter, causing the server to drop new legitimate client queries and degrade resolution services."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, ensure that Unbound is configured with `serve-expired-client-timeout` not greater than `discard-timeout` when `serve-expired: yes` is enabled. Alternatively, disable the `serve-expired` feature if it is not required. Red Hat's default configurations for Unbound prevent this vulnerability from being exploited."}, "name": "CVE-2026-56444", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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": "Fix deferred", "package_name": "unbound", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "unbound", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-07-22T13:10:34Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-56444\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-56444\nhttps://www.nlnetlabs.nl/downloads/unbound/CVE-2026-56444.txt"], "statement": "This Low-impact flaw in Unbound can lead to a denial of service. While a remote attacker could exhaust the reply address counter with specially crafted queries, Red Hat products are not affected by default. The vulnerability requires specific non-default `serve-expired` and `discard-timeout` configurations, which are not present in standard Red Hat deployments.", "threat_severity": "Low"}

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