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Vulnerability details: VCID-nxtc-6zwj-mkha
Vulnerability ID VCID-nxtc-6zwj-mkha
Aliases 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.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 5.6 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3672.json
epss 0.00067 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00067 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00067 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00067 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00067 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
epss 0.00113 https://api.first.org/data/v1/epss?cve=CVE-2021-3672
ssvc Track https://bugzilla.redhat.com/show_bug.cgi?id=1988342
ssvc Track https://c-ares.haxx.se/adv_20210810.html
ssvc Track https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
cvssv3.1 8.1 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-3672
cvssv3.1 5.6 https://nvd.nist.gov/vuln/detail/CVE-2021-3672
archlinux Medium https://security.archlinux.org/AVG-2268
ssvc Track https://security.gentoo.org/glsa/202401-02
ssvc Track https://www.oracle.com/security-alerts/cpujul2022.html
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3672.json
https://api.first.org/data/v1/epss?cve=CVE-2021-3672
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
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3672
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://www.oracle.com/security-alerts/cpujul2022.html
202401-02 https://security.gentoo.org/glsa/202401-02
992053 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=992053
ASA-202108-13 https://security.archlinux.org/ASA-202108-13
AVG-2268 https://security.archlinux.org/AVG-2268
cpe:2.3:a:c-ares_project:c-ares:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:c-ares_project:c-ares:*:*:*:*:*:*:*:*
cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.7:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux:7.7:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_computer_node:1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_computer_node:1:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:7.7:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_eus:7.7:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=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:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_tus:8.4:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:redhat:enterprise_linux_workstation:1:*:*:*:*:*:*:*
CVE-2021-3672 https://nvd.nist.gov/vuln/detail/CVE-2021-3672
RHSA-2021:3280 https://access.redhat.com/errata/RHSA-2021:3280
RHSA-2021:3281 https://access.redhat.com/errata/RHSA-2021:3281
RHSA-2021:3623 https://access.redhat.com/errata/RHSA-2021:3623
RHSA-2021:3638 https://access.redhat.com/errata/RHSA-2021:3638
RHSA-2021:3639 https://access.redhat.com/errata/RHSA-2021:3639
RHSA-2021:3666 https://access.redhat.com/errata/RHSA-2021:3666
RHSA-2022:2043 https://access.redhat.com/errata/RHSA-2022:2043
USN-5034-1 https://usn.ubuntu.com/5034-1/
USN-5034-2 https://usn.ubuntu.com/5034-2/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3672.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-10-15T17:09:33Z/ Found at https://bugzilla.redhat.com/show_bug.cgi?id=1988342
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-10-15T17:09:33Z/ Found at https://c-ares.haxx.se/adv_20210810.html
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-10-15T17:09:33Z/ Found at https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3672
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3672
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-10-15T17:09:33Z/ Found at https://security.gentoo.org/glsa/202401-02
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-10-15T17:09:33Z/ Found at https://www.oracle.com/security-alerts/cpujul2022.html
Exploit Prediction Scoring System (EPSS)
Percentile 0.21155
EPSS Score 0.00067
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:32:12.101222+00:00 Alpine Linux Importer Import https://secdb.alpinelinux.org/v3.13/main.json 37.0.0