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The highest threat from this vulnerability is to data integrity."}, {"lang": "es", "value": "Se encontr\u00f3 un fallo en dnsmasq en versiones anteriores a 2.85. Cuando es configurado para usar un servidor espec\u00edfico para una interfaz de red determinada, dnsmasq usa un puerto fijado para enviar consultas. Un atacante en la red, capaz de encontrar el puerto de salida usado por dnsmasq, solo necesita adivinar la ID de transmisi\u00f3n aleatoria para falsificar una respuesta y lograr que dnsmasq la acepte. Este fallo hace que un ataque de envenenamiento de cach\u00e9 de DNS sea mucho m\u00e1s f\u00e1cil. La mayor amenaza de esta vulnerabilidad es la integridad de los datos"}], "id": "CVE-2021-3448", "lastModified": "2025-12-03T01:15:46.820", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "MEDIUM", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "NONE", "baseScore": 4.3, "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N", "version": "2.0"}, "exploitabilityScore": 8.6, "impactScore": 2.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 4.0, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "nvd@nist.gov", "type": "Primary"}, {"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 4.0, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}, "published": "2021-04-08T23:15:12.597", "references": [{"source": "secalert@redhat.com", "tags": ["Exploit", "Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1939368"}, {"source": "secalert@redhat.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CVTJUOFFFHINLKWAOC2ZSC5MOPD4SJ24/"}, {"source": "secalert@redhat.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FHG7GWSQWKF7JXIMLOGJBKZWBB4VIAJ7/"}, {"source": "secalert@redhat.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GHURNEHHUBSW45KMIZ4FNBCSUPWPGV5V/"}, {"source": "secalert@redhat.com", "tags": ["Third Party Advisory"], "url": "https://security.gentoo.org/glsa/202105-20"}, {"source": "secalert@redhat.com", "tags": ["Patch", "Third Party Advisory"], "url": "https://www.oracle.com/security-alerts/cpujan2022.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Exploit", "Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1939368"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CVTJUOFFFHINLKWAOC2ZSC5MOPD4SJ24/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FHG7GWSQWKF7JXIMLOGJBKZWBB4VIAJ7/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GHURNEHHUBSW45KMIZ4FNBCSUPWPGV5V/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://security.gentoo.org/glsa/202105-20"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://www.oracle.com/security-alerts/cpujan2022.html"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-358"}], "source": "secalert@redhat.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "NVD-CWE-Other"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"acknowledgement": "This issue was discovered by Petr Mensik (Red Hat).", "affected_release": [{"advisory": "RHSA-2021:4153", "cpe": "cpe:/a:redhat:enterprise_linux:8", "package": "dnsmasq-0:2.79-19.el8", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2021-11-09T00:00:00Z"}], "bugzilla": {"description": "dnsmasq: fixed outgoing port used when --server is used with an interface name", "id": "1939368", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1939368"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.0", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N", "status": "verified"}, "cwe": "CWE-358", "details": ["A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.", "A flaw was found in dnsmasq. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity."], "mitigation": {"lang": "en:us", "value": "The flaw can be prevented by removing `--server=<address>@<interface>` option or by removing the directive `server=<address>@<interface>`. If dnsmasq is being run through NetworkManager, please be aware that NetworkManager automatically configures dnsmasq to use the `server=<address>@<interface>` directive, thus in this case the only way to prevent the flaw is to remove `dns=dnsmasq` from /etc/NetworkManager/NetworkManager.conf file.\nIf the `server=<address>@<interface>` must be kept active, the impact of this flaw can be reduced by disabling the dnsmasq cache by adding `--cache-size=0` when calling dnsmasq or by adding a line with `cache-size=0` to the dnsmasq configuration file (/etc/dnsmasq.conf by default). If dnsmasq is being run through NetworkManager, create a new file in /etc/NetworkManager/dnsmasq.d/ and add `cache-size=0` to it.\nBy disabling the cache, you may experience a performance loss in your environment due to all DNS queries being forwarded to the upstream servers. Please evaluate if the mitigation is appropriate for the system\u2019s environment before applying."}, "name": "CVE-2021-3448", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "dnsmasq", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "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": "2021-03-12T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-3448\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-3448"], "threat_severity": "Moderate"}

{}