CVE-2023-32067Network attack vector

DNS resolution interruption via zero-length UDP reply

Published May 25, 2023 · Updated Feb 13, 2025

Denial of service in c-ares before 1.19.1 allows remote attackers to interrupt DNS resolution with a zero-length UDP reply. The read_udp_packets function treats a zero return from recvfrom as a closed connection and calls handle_error instead of ignoring the empty datagram. Exploitation requires a target query and a forged response from its resolver; the affected lookup fails without reported data exposure or modification.

CVSS severity7.5
High
EPSS probability1.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in c-ares before 1.19.1 allows remote attackers to interrupt DNS resolution with a zero-length UDP reply. The read_udp_packets function treats a zero return from recvfrom as a closed connection and calls handle_error instead of ignoring the empty datagram. Exploitation requires a target query and a forged response from its resolver; the affected lookup fails without reported data exposure or modification.

The record

CVE
CVE-2023-32067
Published
May 25, 2023
Updated
Feb 13, 2025
Vendor
Debian
Product
Debian GNU/Linux
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0
  2. Affected versionversion=11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Debian · Debian GNU/Linuxversion=10.0; version=11.0
Fedora Project · Fedora Linuxversion=37; version=38
c-ares Project · c-aresversion=0 <1.19.1; version=< 1.19.1

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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