CVE-2023-32067 | 0-byte UDP payload DoS in c-ares

c-ares is an asynchronous resolver library. c-ares is vulnerable to denial of service. If a target resolver sends a query, the attacker forges a malformed UDP packet with a length of 0 and returns them to the target resolver. The target resolver erroneously interprets the 0 length as a graceful shutdown of the connection. This issue has been patched in version 1.19.1.

Published: 2023-05-25 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-32067 is rated Moderate Risk (56.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.58%). EPSS rose +1.18% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-32067

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.40% 1.58% +1.18%
2 2026-06-12 0.34% 0.40% +0.05%
3 2026-05-20 — 0.34% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-32067

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-32067

OS Trackers for CVE-2023-32067

vendor priority summary link
alpine high CVE-2023-32067: 1 source package rows (c-ares); 5 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 5. https://security.alpinelinux.org/vuln/CVE-2023-32067
debian not yet assigned CVE-2023-32067 not yet assigned priority: Debian including 1 source packages (c-ares), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-32067
gentoo normal CVE-2023-32067: 1 GLSA(s) (202310-09), 1 atom(s) (net-dns/c-ares); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-32067
redhat high — https://access.redhat.com/security/cve/CVE-2023-32067
suse high CVE-2023-32067 severity important: SUSE including 309 source package names (0.3.2-1.2:libcares2-1.19.1-150000.3.23.1, 0.3.32-3.4:libcares2-1.19.1-150000.3.23.1, …), 696 product×package rows across 319 product lines (Container bci/nodejs, Container caasp/v4/cilium, … (319 product lines)): Fixed 544, Known Affected 152. https://www.suse.com/security/cve/CVE-2023-32067/
ubuntu medium CVE-2023-32067 medium priority: Ubuntu including 1 source packages (c-ares), 9 status rows across 9 suites (bionic, focal, jammy, kinetic, lunar, mantic, trusty, upstream, xenial): released 7, ignored 1, not-affected 1. https://ubuntu.com/security/CVE-2023-32067

Affected software / configurations for CVE-2023-32067

Vendor Product Version Raw CPE
c-ares_project c-ares < 1.19.1 cpe:2.3:a:c-ares_project:c-ares:*:*:*:*:*:*:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2023-32067

cvelogic Threat Intelligence