CVE-2023-32067: 0-byte UDP payload DoS in c-ares
Vulnerability summary
CVE-2023-32067 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in c-ares_project c-ares. EPSS estimates a 1.56% chance of exploitation in the next 30 days, higher than 75.3% of scored vulnerabilities.
Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 2% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 19 · Related 12Timeline
- 25-05-2023PublishedVulnerability first disclosed.
- 13-02-2025Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · Red hatEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · WolfiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · ChainguardEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
1.56%
Chance of exploitation in the next 30 days
Percentile
75%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.56% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat4 products
- c-ares< 0:1.17.1-5.el9_2.1 | < 0:1.17.1-5.el9_0.1 | < 0:1.13.0-6.el8_8.2 | < 0:1.13.0-5.el8_2.1 | < 0:1.13.0-6.el8_6.1 | < 0:1.13.0-5.el8_1.1 | < 0:1.13.0-5.el8_4.2 | < 0:1.10.0-3.el7_9.1
- c-ares-debuginfo< 0:1.17.1-5.el9_2.1 | < 0:1.17.1-5.el9_0.1 | < 0:1.13.0-6.el8_8.2 | < 0:1.13.0-5.el8_2.1 | < 0:1.13.0-6.el8_6.1 | < 0:1.13.0-5.el8_1.1 | < 0:1.13.0-5.el8_4.2 | < 0:1.10.0-3.el7_9.1
- c-ares-debugsource< 0:1.17.1-5.el9_2.1 | < 0:1.17.1-5.el9_0.1 | < 0:1.13.0-6.el8_8.2 | < 0:1.13.0-5.el8_2.1 | < 0:1.13.0-6.el8_6.1 | < 0:1.13.0-5.el8_1.1 | < 0:1.13.0-5.el8_4.2
- c-ares-devel< 0:1.17.1-5.el9_2.1 | < 0:1.17.1-5.el9_0.1 | < 0:1.13.0-6.el8_8.2 | < 0:1.13.0-5.el8_2.1 | < 0:1.13.0-6.el8_6.1 | < 0:1.13.0-5.el8_1.1 | < 0:1.13.0-5.el8_4.2 | < 0:1.10.0-3.el7_9.1
Debian2 products
- c-ares< 1.18.1-3
- debian_linuxEOL10.0 | 11.0
C-ares1 product
- c-ares< 1.19.1
C-ares_project1 product
- c-ares< 1.19.1
Chainguard1 product
- c-ares< 1.19.1-r0
Fedoraproject1 product
- fedoraEOL37 | 38
Ubuntu1 product
- c-ares< 1.10.0-3ubuntu0.2+esm2 | < 1.14.0-1ubuntu0.2+esm1 | < 1.15.0-1ubuntu0.3 | < 1.18.1-1ubuntu0.22.04.2
Wolfi1 product
- c-ares< 1.19.1-r0
8 vendors · 12 products
References
35 links- github.com/c-ares/c-ares/security/advisories/GHSA-9g78-jv2r-p7vcX Refsource CONFIRMARTICLEREPORTAdvisoryThird Party Advisory
