NVD / CVE Program· CNA GitHub_M

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

Noroxi assessment

Priority: Monitor (action score 30/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 1.5% (FIRST EPSS); higher than 75.2% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: c-ares c-ares 1.19.1; azl3 grpc 1.42.0-7 on Azure Linux 3.0 1.62.0-2; azl3 grpc 1.62.0-2 on Azure Linux 3.0 1.62.0-2.

Low priority for now. Upgrade to c-ares c-ares 1.19.1; azl3 grpc 1.42.0-7 on Azure Linux 3.0 1.62.0-2; azl3 grpc 1.62.0-2 on Azure Linux 3.0 1.62.0-2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available

Published: May 25, 2023
Updated: Jun 17, 2026
EPSS: 1.5% · 75th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 1.5%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.5
CNA · GitHub_M: 7.5; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
c-ares project	c-ares	cpe:2.3:a:c-ares_project:c-ares
fedoraproject	fedora	cpe:2.3:o:fedoraproject:fedora
debian	debian linux	cpe:2.3:o:debian:debian_linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

c-ares project c-aresbefore 1.19.1
debian debian linux10.0
debian debian linux11.0
fedoraproject fedora37
fedoraproject fedora38

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

c-ares c-ares
- < 1.19.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

+96

Same product

c-ares project: all records

Other highest-scoring records for the same primary product.

CVE-2022-4904A flaw was found in the c-ares package.
34Monitor
CVE-2023-31147Insufficient randomness in generation of DNS query IDs in c-ares
26Monitor
CVE-2023-31130Buffer Underwrite in ares_inet_net_pton()
25Monitor

Published before and after this one in the same product

← EarlierCVE-2021-3672Nov 23, 2021 · 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 o
23Monitor
← EarlierCVE-2023-31124May 25, 2023 · AutoTools does not set CARES_RANDOM_FILE during cross compilation
14Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
c-ares c-ares	1.19.1 · description	Vendor (CNA)
azl3 grpc 1.42.0-7 on Azure Linux 3.0	1.62.0-2 · CBL-Mariner Releases	Microsoft (MSRC)
azl3 grpc 1.62.0-2 on Azure Linux 3.0	1.62.0-2 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 c-ares 1.19.1-1 on CBL Mariner 2.0	1.19.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 fluent-bit 2.1.10-1 on CBL Mariner 2.0	2.1.10-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 grpc 1.42.0-8 on CBL Mariner 2.0	1.42.0-8 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 nodejs 16.20.1-2 on CBL Mariner 2.0	16.20.1-2 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 nodejs18 18.17.1-2 on CBL Mariner 2.0	18.17.1-2 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 python-gevent 21.1.2-3 on CBL Mariner 2.0	21.1.2-3 · CBL-Mariner Releases	Microsoft (MSRC)
cm1 c-ares 1.19.1-1 on CBL Mariner 1.0	1.19.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
almalinux:c-ares	1.17.1-5.el9_2.1 · AlmaLinux:9	Package registry (OSV)
almalinux:c-ares-devel	1.17.1-5.el9_2.1 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs	1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-devel	1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-docs	1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-full-i18n	1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-libs	1:16.19.1-2.el9_2 · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-nodemon	2.0.20-2.module_el9.2.0+29+de583a0b · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-packaging	2021.06-4.module_el9.1.0+13+d9a595ea · AlmaLinux:9	Package registry (OSV)
almalinux:nodejs-packaging-bundler	2021.06-4.module_el9.1.0+13+d9a595ea · AlmaLinux:9	Package registry (OSV)
almalinux:npm	1:9.5.0-1.18.14.2.3.module_el9.2.0+30+e3312493 · AlmaLinux:9	Package registry (OSV)
debian:c-ares	1.18.1-3 · Debian:12	Package registry (OSV)
opensuse:c-ares	1.19.1-150000.3.23.1 · openSUSE:Leap Micro 5.3	Package registry (OSV)
opensuse:nodejs16	16.20.1-150400.3.21.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:nodejs18	18.16.1-150400.9.9.1 · openSUSE:Leap 15.4	Package registry (OSV)
red hat:c-ares	0:1.17.1-5.el9_2.1 · Red Hat:enterprise_linux:9::baseos	Package registry (OSV)
red hat:c-ares-debuginfo	0:1.17.1-5.el9_2.1 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:c-ares-debugsource	0:1.17.1-5.el9_2.1 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:c-ares-devel	0:1.17.1-5.el9_2.1 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:nodejs	1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)

+17

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

Fix✗ → ✓Sep 28, 2026, 10:44 PM UTC

For records you follow, these changes also arrive as notifications. →

References

security.netapp.com/advisory/ntap-20240605-0004/

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	c-ares	before 1.13.0-6.el8_8.2	1.13.0-6.el8_8.2
AlmaLinux:8	c-ares-devel	before 1.13.0-6.el8_8.2	1.13.0-6.el8_8.2
AlmaLinux:8	nodejs	before 1:16.19.1-2.module_el8.8.0+3586+d4fc0b72	1:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8	nodejs	before 1:18.14.2-3.module_el8.8.0+3587+ee652244	1:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8	nodejs-devel	before 1:16.19.1-2.module_el8.8.0+3586+d4fc0b72	1:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8	nodejs-devel	before 1:18.14.2-3.module_el8.8.0+3587+ee652244	1:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8	nodejs-docs	before 1:16.19.1-2.module_el8.8.0+3586+d4fc0b72	1:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8	nodejs-docs	before 1:18.14.2-3.module_el8.8.0+3587+ee652244	1:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8	nodejs-full-i18n	before 1:16.19.1-2.module_el8.8.0+3586+d4fc0b72	1:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8	nodejs-full-i18n	before 1:18.14.2-3.module_el8.8.0+3587+ee652244	1:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8	nodejs-nodemon	before 2.0.20-2.module_el8.8.0+3587+ee652244	2.0.20-2.module_el8.8.0+3587+ee652244
AlmaLinux:8	nodejs-nodemon	before 2.0.20-3.module_el8.8.0+3586+d4fc0b72	2.0.20-3.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8	nodejs-packaging	before 2021.06-4.module_el8.7.0+3343+ea2b7901	2021.06-4.module_el8.7.0+3343+ea2b7901
AlmaLinux:8	nodejs-packaging	before 25-1.module_el8.5.0+2605+45d748af	25-1.module_el8.5.0+2605+45d748af
AlmaLinux:8	nodejs-packaging-bundler	before 2021.06-4.module_el8.7.0+3343+ea2b7901	2021.06-4.module_el8.7.0+3343+ea2b7901
AlmaLinux:8	npm	before 1:9.5.0-1.18.14.2.3.module_el8.8.0+3587+ee652244	1:9.5.0-1.18.14.2.3.module_el8.8.0+3587+ee652244
AlmaLinux:8	npm	before 1:8.19.3-1.16.19.1.2.module_el8.8.0+3586+d4fc0b72	1:8.19.3-1.16.19.1.2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:9	c-ares	before 1.17.1-5.el9_2.1	1.17.1-5.el9_2.1
AlmaLinux:9	c-ares-devel	before 1.17.1-5.el9_2.1	1.17.1-5.el9_2.1
AlmaLinux:9	nodejs	before 1:18.14.2-3.module_el9.2.0+30+e3312493	1:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9	nodejs	before 1:16.19.1-2.el9_2	1:16.19.1-2.el9_2
AlmaLinux:9	nodejs-devel	before 1:18.14.2-3.module_el9.2.0+30+e3312493	1:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9	nodejs-docs	before 1:16.19.1-2.el9_2	1:16.19.1-2.el9_2
AlmaLinux:9	nodejs-docs	before 1:18.14.2-3.module_el9.2.0+30+e3312493	1:18.14.2-3.module_el9.2.0+30+e3312493