Medium
Security advisory
A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-3672
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 06:03 UTC · Revision 1
Source evidence
A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.
osv:CVE-2021-3672
Complete source record
{
"id": "a3f0f78bc8f72f5085fb7c3dbfc94242ae0046e7c3b0f946e27738ce155b1c6b",
"url": "https://osv.dev/vulnerability/CVE-2021-3672",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3672",
"summary": "A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.",
"evidence": "osv:CVE-2021-3672",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-3672",
"aliases": [
"BIT-node-2021-3672",
"BIT-node-min-2021-3672",
"BIT-pgbouncer-2021-3672",
"CVE-2021-3672"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/c-ares/c-ares",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "6654436a307a5a686b008c1d4c93b0085da6e6d8"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:c-ares_project:c-ares:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.0"
},
{
"fixed": "1.17.2"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"cares-1_17_1",
"c-ares-1_17_0",
"cares-1_16_1",
"cares-1_16_0",
"cares-1_15_0",
"cares-1_14_0",
"cares-1_13_0",
"cares-1_12_0",
"cares-1_11_0",
"cares-1_11_0-rc1",
"cares-1_10_0",
"cares-1_9_1",
"cares-1_9_0",
"cares-1_8_0",
"cares-1_7_5",
"cares-1_7_4",
"cares-1_7_3",
"cares-1_7_2",
"cares-1_7_1",
"curl-7_20_0",
"cares-1_7_0",
"curl-7_19_7",
"curl-7_19_6",
"curl-7_19_5",
"curl-7_19_4",
"curl-7_19_3",
"cares-1_6_0",
"curl-7_19_2",
"curl-7_19_0",
"cares-1_5_3",
"curl-7_18_2",
"cares-1_5_2",
"curl-7_18_1",
"curl-7_18_0",
"cares-1_5_1",
"cares-1_5_0",
"curl-7_17_1",
"curl-7_17_0",
"curl-7_16_4",
"curl-7_16_3",
"cares-1_4_0",
"curl-7_16_2",
"curl-7_16_1",
"cares-1_3_2",
"curl-7_16_0",
"curl-7_15_6-prepipeline",
"curl-7_15_5",
"cares-1_3_1",
"curl-7_15_4",
"curl-7_15_3",
"curl-7_15_1",
"curl-7_15_0",
"curl-7_14_1",
"curl-7_14_0",
"curl-7_13_2",
"curl-7_13_1",
"curl-7_13_0",
"cares-1_2_1",
"curl-7_12_2",
"curl-7_12_1",
"curl-7_12_0",
"c-ares-1_2_0",
"curl-7_11_1",
"cares-1_1_0",
"curl-7_11_0",
"curl-7_10_8"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3672.json"
}
},
{
"ranges": [
{
"repo": "https://github.com/nodejs/node",
"type": "GIT",
"events": [
{
"introduced": "2f45ad8060e13d5ac912335096d21526f2f9602b"
},
{
"last_affected": "921493e2287aa895679620155b5288b2e1587bfd"
},
{
"introduced": "42cce5a9d0fd905bf4ad7a2528c36572dfb8b5ad"
},
{
"fixed": "151261efb8b85696620f80ecc1f50d9c1f886a1b"
},
{
"introduced": "73aa21658dfa6a22c06451d080152b32b1f98dbe"
},
{
"last_affected": "354b6a93bd1d66f1833489d6fe01a2b0e8f6aff9"
},
{
"introduced": "c1da528bc25c9cc5a8240a7b4f136f5968f6e113"
},
{
"fixed": "db159ab870b1aa7f55e4e450c81764f22bf0ef80"
},
{
"introduced": "7162e686b18d22b4385fa5c04274fb04dbd810c7"
},
{
"fixed": "bfe80913e88139da1aa283475cdbc060ea98ae6f"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*",
"range": [
{
"introduced": "12.0.0"
},
{
"last_affected": "12.12.0"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*",
"range": [
{
"introduced": "12.13.0"
},
{
"fixed": "12.22.5"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*",
"range": [
{
"introduced": "14.0.0"
},
{
"last_affected": "14.14.0"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*",
"range": [
{
"introduced": "14.15.0"
},
{
"fixed": "14.17.5"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*",
"range": [
{
"introduced": "16.0.0"
},
{
"fixed": "16.6.2"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v16.6.1",
"v16.6.0",
"v14.17.4",
"v12.22.4",
"v16.5.0",
"v16.4.2",
"v14.17.3",
"v12.22.3",
"v14.17.2",
"v16.4.1",
"v12.22.2",
"v16.4.0",
"v14.17.1",
"v16.3.0",
"v16.2.0",
"v14.17.0",
"v16.1.0",
"v16.0.0",
"v14.16.1",
"v12.22.1",
"v12.22.0",
"v14.16.0",
"v12.21.0",
"v12.20.2",
"v14.15.5",
"v14.15.4",
"v12.20.1",
"v14.15.3",
"v14.15.2",
"v12.20.0",
"v12.19.1",
"v14.15.1",
"v14.15.0",
"v14.14.0",
"v14.13.1",
"v12.19.0",
"v14.13.0",
"v14.12.0",
"v12.18.4",
"v14.11.0",
"v14.10.1",
"v14.10.0",
"v14.9.0",
"v14.8.0",
"v14.7.0",
"v12.18.3",
"v14.6.0",
"v14.5.0",
"v12.18.2",
"v12.18.1",
"v12.18.0",
"v14.4.0",
"v12.17.0",
"v14.3.0",
"v14.2.0",
"v14.1.0",
"v12.16.3",
"v14.0.0",
"v12.16.2",
"v12.16.1",
"v12.16.0",
"v12.15.0",
"v12.14.1",
"v12.14.0",
"v12.13.1",
"v12.13.0",
"v12.12.0",
"v12.11.1",
"v12.11.0",
"v12.10.0",
"v12.9.1",
"v12.9.0",
"v12.8.1",
"v12.8.0",
"v12.7.0",
"v12.6.0",
"v12.5.0",
"v12.4.0",
"v12.3.1",
"v12.3.0",
"v12.2.0",
"v12.1.0",
"v12.0.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3672.json"
}
}
],
"modified": "2026-10-24T10:30:34.658827464Z",
"provider": "osv",
"references": [
"https://security.gentoo.org/glsa/202401-02",
"https://www.oracle.com/security-alerts/cpujul2022.html",
"https://bugzilla.redhat.com/show_bug.cgi?id=1988342",
"https://c-ares.haxx.se/adv_20210810.html",
"https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:*"
],
"vendor_product": "pgbouncer:pgbouncer",
"extracted_events": [
{
"range": [
{
"last_affected": "1.17.0"
}
],
"source": "CPE_RANGE"
}
]
},
{
"cpes": [
"cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:*"
],
"vendor_product": "siemens:sinec_infrastructure_network_services",
"extracted_events": [
{
"range": [
{
"fixed": "1.0.1.1"
}
],
"source": "CPE_RANGE"
}
]
},
{
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
{
"introduced": "33"
},
{
"last_affected": "33"
},
{
"introduced": "34"
},
{
"last_affected": "34"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:7.7:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux",
"extracted_events": [
{
"range": [
{
"introduced": "7.0"
},
{
"last_affected": "7.0"
},
{
"introduced": "7.7"
},
{
"last_affected": "7.7"
},
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_computer_node:1:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_computer_node",
"extracted_events": [
{
"range": [
{
"introduced": "1"
},
{
"last_affected": "1"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_eus:7.7:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_eus",
"extracted_events": [
{
"range": [
{
"introduced": "7.7"
},
{
"last_affected": "7.7"
},
{
"introduced": "8.1"
},
{
"last_affected": "8.1"
},
{
"introduced": "8.2"
},
{
"last_affected": "8.2"
},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_for_ibm_z_systems",
"extracted_events": [
{
"range": [
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.1:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_for_ibm_z_systems_eus",
"extracted_events": [
{
"range": [
{
"introduced": "8.1"
},
{
"last_affected": "8.1"
},
{
"introduced": "8.2"
},
{
"last_affected": "8.2"
},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_for_power_little_endian",
"extracted_events": [
{
"range": [
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.1:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_for_power_little_endian_eus",
"extracted_events": [
{
"range": [
{
"introduced": "8.1"
},
{
"last_affected": "8.1"
},
{
"introduced": "8.2"
},
{
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},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_server_aus",
"extracted_events": [
{
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{
"introduced": "8.2"
},
{
"last_affected": "8.2"
},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_server_tus",
"extracted_events": [
{
"range": [
{
"introduced": "8.2"
},
{
"last_affected": "8.2"
},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.2:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_server_update_services_for_sap_solutions",
"extracted_events": [
{
"range": [
{
"introduced": "8.1"
},
{
"last_affected": "8.1"
},
{
"introduced": "8.2"
},
{
"last_affected": "8.2"
},
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_tus:8.4:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_tus",
"extracted_events": [
{
"range": [
{
"introduced": "8.4"
},
{
"last_affected": "8.4"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux_workstation:1:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux_workstation",
"extracted_events": [
{
"range": [
{
"introduced": "1"
},
{
"last_affected": "1"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-3672",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 433569,
"published_at": "2021-11-23T19:15:07.877+00:00"
}