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The highest threat from this vulnerability is to system availability."}, {"lang": "es", "value": "Se encontr\u00f3 un fallo en dnsmasq versiones anteriores a 2.83. Se detect\u00f3 un desbordamiento del b\u00fafer en la regi\u00f3n heap de la memoria en dnsmasq cuando DNSSEC est\u00e1 habilitado y antes de comprobar las entradas DNS recibidas. Un atacante remoto, que puede crear respuestas DNS v\u00e1lidas, podr\u00eda usar este fallo para causar un desbordamiento en una memoria asignada de la pila. Este fallo es causado por una falta de comprobaci\u00f3n de longitud en rfc1035.c:extract_name(), que podr\u00eda ser abusado para causar que el c\u00f3digo ejecute memcpy() con un tama\u00f1o negativo en get_rdata() y causar un bloqueo en dnsmasq, lo que resultar\u00eda en una denegaci\u00f3n de servicio. La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema"}], "id": "CVE-2020-25683", "lastModified": "2025-11-04T20:15:57.093", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "HIGH", "cvssData": {"accessComplexity": "MEDIUM", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "COMPLETE", "baseScore": 7.1, "confidentialityImpact": "NONE", "integrityImpact": "NONE", "vectorString": "AV:N/AC:M/Au:N/C:N/I:N/A:C", "version": "2.0"}, "exploitabilityScore": 8.6, "impactScore": 6.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2021-01-20T16:15:14.087", "references": [{"source": "secalert@redhat.com", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1882018"}, {"source": "secalert@redhat.com", "tags": ["Mailing List", "Third Party Advisory"], "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html"}, {"source": "secalert@redhat.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/"}, {"source": "secalert@redhat.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/"}, {"source": "secalert@redhat.com", "tags": ["Third Party Advisory"], "url": "https://security.gentoo.org/glsa/202101-17"}, {"source": "secalert@redhat.com", "tags": ["Third Party Advisory"], "url": "https://www.debian.org/security/2021/dsa-4844"}, {"source": "secalert@redhat.com", "tags": ["Third Party Advisory"], "url": "https://www.jsof-tech.com/disclosures/dnspooq/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1882018"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"], "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://security.gentoo.org/glsa/202101-17"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://www.debian.org/security/2021/dsa-4844"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://www.jsof-tech.com/disclosures/dnspooq/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://www.kb.cert.org/vuls/id/434904"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-122"}], "source": "secalert@redhat.com", "type": "Secondary"}]}

{"acknowledgement": "Red Hat would like to thank Moshe Kol (JSOF) and Shlomi Oberman (JSOF) for reporting this issue.", "affected_release": [{"advisory": "RHSA-2021:0150", "cpe": "cpe:/a:redhat:enterprise_linux:8", "package": "dnsmasq-0:2.79-13.el8_3.1", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2021-01-19T00:00:00Z"}, {"advisory": "RHSA-2021:0152", "cpe": "cpe:/a:redhat:rhel_eus:8.1", "package": "dnsmasq-0:2.79-6.el8_1.1", "product_name": "Red Hat Enterprise Linux 8.1 Extended Update Support", "release_date": "2021-01-19T00:00:00Z"}, {"advisory": "RHSA-2021:0151", "cpe": "cpe:/a:redhat:rhel_eus:8.2", "package": "dnsmasq-0:2.79-11.el8_2.2", "product_name": "Red Hat Enterprise Linux 8.2 Extended Update Support", "release_date": "2021-01-19T00:00:00Z"}], "bugzilla": {"description": "dnsmasq: heap-based buffer overflow with large memcpy in get_rdata() when DNSSEC is enabled", "id": "1882018", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1882018"}, "csaw": true, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "verified"}, "cwe": "CWE-122", "details": ["A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.", "A flaw was found in dnsmasq. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability."], "mitigation": {"lang": "en:us", "value": "The only known way to mitigate this flaw is to disable DNSSEC altogether, by removing the `--dnssec` command line option or the `dnssec` option from dnsmasq configuration file."}, "name": "CVE-2020-25683", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:5", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 5"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openstack:10", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat OpenStack Platform 10 (Newton)"}, {"cpe": "cpe:/a:redhat:openstack:13", "fix_state": "Not affected", "package_name": "dnsmasq", "product_name": "Red Hat OpenStack Platform 13 (Queens)"}], "public_date": "2021-01-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2020-25683\nhttps://nvd.nist.gov/vuln/detail/CVE-2020-25683\nhttps://www.jsof-tech.com/disclosures/dnspooq/"], "statement": "This issue does not affect the versions of dnsmasq as shipped with Red Hat Enterprise Linux 5, 6, and 7 as they are not compiled with DNSSEC support.", "threat_severity": "Moderate"}