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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. Este fallo permite a un atacante remoto, que puede crear respuestas DNS v\u00e1lidas, causar un desbordamiento en una memoria asignada a la pila. Este fallo es causado por una falta de comprobaci\u00f3n de longitud en la funci\u00f3n rfc1035.c:extract_name(), que podr\u00eda ser abusado para hacer que el c\u00f3digo ejecutar memcpy() con un tama\u00f1o negativo en sort_rrset() y causar un bloqueo en dnsmasq, resultando en una denegaci\u00f3n de servicio. La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema"}], "id": "CVE-2020-25687", "lastModified": "2025-11-04T20:15:57.610", "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": "2021-01-20T17:15:13.060", "references": [{"source": "secalert@redhat.com", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1891568"}, {"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=1891568"}, {"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 sort_rrset() when DNSSEC is enabled", "id": "1891568", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1891568"}, "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. This flaw allows a remote attacker, who can create valid DNS replies, 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 sort_rrset() 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. This flaw allows a remote attacker, who can create valid DNS replies, 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 sort_rrset() 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-2020-25687", "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-2020-25687\nhttps://nvd.nist.gov/vuln/detail/CVE-2020-25687\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"}