What’s Vulnerable › Vulnerabilities
CVE-2021-3672
- Severity: medium (CVSS 5.6 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.8% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2021-11-23 · updated 2026-06-17
- Weakness: CWE-79
Description
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.
Affected products
- C-Ares Project C-Ares: from 1.0.0 before 1.17.2 — fixed in 1.17.2
- Fedoraproject Fedora: 33, 34
- Node.js: from 12.0.0 through 12.12.0; from 12.13.0 before 12.22.5; from 14.0.0 through 14.14.0; from 14.15.0 before 14.17.5; from 16.0.0 before 16.6.2 — fixed in 12.22.5, 14.17.5, 16.6.2
- PgBouncer: through 1.17.0
- Red Hat Enterprise Linux: 7.0, 7.7, 8.0
- RedHat Enterprise Linux Computer Node: 1
- RedHat Enterprise Linux Eus: 7.7, 8.1, 8.2, 8.4
- RedHat Enterprise Linux For Ibm Z Systems: 8.0
- RedHat Enterprise Linux For Ibm Z Systems Eus: 8.1, 8.2, 8.4
- RedHat Enterprise Linux For Power Little Endian: 8.0
- RedHat Enterprise Linux For Power Little Endian Eus: 8.1, 8.2, 8.4
- RedHat Enterprise Linux Server Aus: 8.2, 8.4
- RedHat Enterprise Linux Server Tus: 8.2, 8.4
- RedHat Enterprise Linux Server Update Services For Sap Solutions: 8.1, 8.2, 8.4
- RedHat Enterprise Linux Tus: 8.4
- RedHat Enterprise Linux Workstation: 1
- Siemens Sinec Infrastructure Network Services: before 1.0.1.1 — fixed in 1.0.1.1
How to fix
Upgrade to a fixed version: C-Ares Project C-Ares 1.17.2; Node.js 12.22.5, 14.17.5, 16.6.2; Siemens Sinec Infrastructure Network Services 1.0.1.1. Check the vendor advisory for mitigations.
References
- 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://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
- https://security.gentoo.org/glsa/202401-02
- https://www.oracle.com/security-alerts/cpujul2022.html
Get alerted when CVE-2021-3672 or the next vulnerability affects your stack