{ "document": { "aggregate_severity": { "text": "Medium" }, "category": "csaf_vex", "csaf_version": "2.0", "distribution": { "text": "TuxCare License Agreement", "tlp": { "label": "WHITE", "url": "https://www.first.org/tlp/" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.", "title": "Terms of Use" } ], "publisher": { "category": "vendor", "contact_details": "https://tuxcare.com/contact/", "name": "TuxCare", "namespace": "https://tuxcare.com/" }, "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://security.tuxcare.com/csaf/v2/els_os/centos6els/vex/2021/cve-2021-25220-els_os-centos6els.json" } ], "tracking": { "current_release_date": "2026-06-12T15:04:36Z", "generator": { "date": "2026-06-12T15:04:36Z", "engine": { "name": "pyCSAF" } }, "id": "CVE-2021-25220-ELS_OS-CENTOS6ELS", "initial_release_date": "2021-01-01T00:00:00Z", "revision_history": [ { "date": "2021-01-01T00:00:00Z", "number": "1", "summary": "Initial version" }, { "date": "2025-10-16T13:17:43Z", "number": "2", "summary": "Official Publication" }, { "date": "2025-12-23T20:26:03Z", "number": "3", "summary": "Update document" }, { "date": "2026-06-12T15:04:36Z", "number": "4", "summary": "Update document" } ], "status": "final", "version": "4" }, "title": "Security update on CVE-2021-25220" }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_name", "name": "Community Enterprise Operating System 6", "product": { "name": "Community Enterprise Operating System 6", "product_id": "CentOS-6", "product_identification_helper": { "cpe": "cpe:2.3:o:centos:centos:6:*:*:*:*:*:*:*" } } } ], "category": "product_family", "name": "Community Enterprise Operating System" } ], "category": "vendor", "name": "Red Hat, Inc." }, { "branches": [ { "branches": [ { "category": "product_version", "name": "dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product": { "name": "dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_id": "dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_identification_helper": { "purl": "pkg:rpm/tuxcare/dhcp-common@4.1.1-64.P1.el6.cloudlinux.els?arch=x86_64&epoch=12" } } } ], "category": "architecture", "name": "x86_64" } ], "category": "vendor", "name": "TuxCare" }, { "branches": [ { "branches": [ { "category": "product_version", "name": "dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product": { "name": "dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_id": "dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_identification_helper": { "purl": "pkg:rpm/cloudlinux/dhcp@4.1.1-64.P1.el6.cloudlinux.els?arch=x86_64&epoch=12" } } }, { "category": "product_version", "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product": { "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_id": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_identification_helper": { "purl": "pkg:rpm/cloudlinux/dhcp-devel@4.1.1-64.P1.el6.cloudlinux.els?arch=x86_64&epoch=12" } } }, { "category": "product_version", "name": "dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product": { "name": "dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_id": "dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "product_identification_helper": { "purl": "pkg:rpm/cloudlinux/dhclient@4.1.1-64.P1.el6.cloudlinux.els?arch=x86_64&epoch=12" } } } ], "category": "architecture", "name": "x86_64" }, { "branches": [ { "category": "product_version", "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "product": { "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "product_id": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "product_identification_helper": { "purl": "pkg:rpm/cloudlinux/dhcp-devel@4.1.1-64.P1.el6.cloudlinux.els?arch=i686&epoch=12" } } } ], "category": "architecture", "name": "i686" } ], "category": "vendor", "name": "CloudLinux" } ], "relationships": [ { "category": "default_component_of", "full_product_name": { "name": "dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64 as a component of Community Enterprise Operating System 6", "product_id": "CentOS-6:dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" }, "product_reference": "dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "relates_to_product_reference": "CentOS-6" }, { "category": "default_component_of", "full_product_name": { "name": "dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64 as a component of Community Enterprise Operating System 6", "product_id": "CentOS-6:dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" }, "product_reference": "dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "relates_to_product_reference": "CentOS-6" }, { "category": "default_component_of", "full_product_name": { "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64 as a component of Community Enterprise Operating System 6", "product_id": "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" }, "product_reference": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "relates_to_product_reference": "CentOS-6" }, { "category": "default_component_of", "full_product_name": { "name": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686 as a component of Community Enterprise Operating System 6", "product_id": "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686" }, "product_reference": "dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "relates_to_product_reference": "CentOS-6" }, { "category": "default_component_of", "full_product_name": { "name": "dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64 as a component of Community Enterprise Operating System 6", "product_id": "CentOS-6:dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" }, "product_reference": "dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "relates_to_product_reference": "CentOS-6" } ] }, "vulnerabilities": [ { "cve": "CVE-2021-25220", "cwe": { "id": "CWE-444", "name": "Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')" }, "notes": [ { "category": "description", "text": "BIND 9.11.0 -> 9.11.36 9.12.0 -> 9.16.26 9.17.0 -> 9.18.0 BIND Supported Preview Editions: 9.11.4-S1 -> 9.11.36-S1 9.16.8-S1 -> 9.16.26-S1 Versions of BIND 9 earlier than those shown - back to 9.1.0, including Supported Preview Editions - are also believed to be affected but have not been tested as they are EOL. The cache could become poisoned with incorrect records leading to queries being made to the wrong servers, which might also result in false information being returned to clients.", "title": "Vulnerability description" }, { "category": "general", "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.", "title": "CVSS score applicability" }, { "category": "other", "text": "TuxCare has assessed that this vulnerability does not impact any currently supported TuxCare products. This evaluation may change as new information becomes available. For additional details regarding this vulnerability and affected products, refer to the provided references.", "title": "Statement" } ], "product_status": { "known_not_affected": [ "CentOS-6:dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" ] }, "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://cve.tuxcare.com/els/cve/CVE-2021-25220" }, { "category": "external", "summary": "https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf", "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf" }, { "category": "external", "summary": "https://kb.isc.org/v1/docs/cve-2021-25220", "url": "https://kb.isc.org/v1/docs/cve-2021-25220" }, { "category": "external", "summary": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2SXT7247QTKNBQ67MNRGZD23ADXU6E5U/", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2SXT7247QTKNBQ67MNRGZD23ADXU6E5U/" }, { "category": "external", "summary": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5VX3I2U3ICOIEI5Y7OYA6CHOLFMNH3YQ/", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5VX3I2U3ICOIEI5Y7OYA6CHOLFMNH3YQ/" }, { "category": "external", "summary": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/API7U5E7SX7BAAVFNW366FFJGD6NZZKV/", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/API7U5E7SX7BAAVFNW366FFJGD6NZZKV/" }, { "category": "external", "summary": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DE3UAVCPUMAKG27ZL5YXSP2C3RIOW3JZ/", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DE3UAVCPUMAKG27ZL5YXSP2C3RIOW3JZ/" }, { "category": "external", "summary": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYD7US4HZRFUGAJ66ZTHFBYVP5N3OQBY/", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYD7US4HZRFUGAJ66ZTHFBYVP5N3OQBY/" }, { "category": "external", "summary": "https://security.gentoo.org/glsa/202210-25", "url": "https://security.gentoo.org/glsa/202210-25" }, { "category": "external", "summary": "https://security.netapp.com/advisory/ntap-20220408-0001/", "url": "https://security.netapp.com/advisory/ntap-20220408-0001/" }, { "category": "external", "summary": "https://supportportal.juniper.net/s/article/2022-10-Security-Bulletin-Junos-OS-SRX-Series-Cache-poisoning-vulnerability-in-BIND-used-by-DNS-Proxy-CVE-2021-25220?language=en_US", "url": "https://supportportal.juniper.net/s/article/2022-10-Security-Bulletin-Junos-OS-SRX-Series-Cache-poisoning-vulnerability-in-BIND-used-by-DNS-Proxy-CVE-2021-25220?language=en_US" } ], "release_date": "2022-03-23T13:15:00Z", "scores": [ { "cvss_v2": { "accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "SINGLE", "availabilityImpact": "NONE", "baseScore": 4.0, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:L/Au:S/C:N/I:P/A:N", "version": "2.0" }, "products": [ "CentOS-6:dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" ] } ], "threats": [ { "category": "impact", "details": "Moderate" }, { "category": "impact", "date": "2026-06-12T13:03:20.273829Z", "details": "Not affected. CVE-2021-25220 targets ISC BIND 9’s DNS forwarding/resolver code (named) that can lead to cache poisoning when using forwarders; the dhcp 4.1.1 codebase implements DHCP server/relay/client functionality and contains no BIND/named or DNS caching/forwarding code. Because the vulnerable BIND component is absent, this CVE does not apply to this project.", "product_ids": [ "CentOS-6:dhclient-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-common-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.i686", "CentOS-6:dhcp-devel-12:4.1.1-64.P1.el6.cloudlinux.els.x86_64" ] } ] } ] }