dbcve.org
FedoraOperating system · Fedoraproject

CVE-2023-32067

HIGH · 7.5 CVSS v3.1 Published 2023-05-25
Fix available
A fix is available. Upgrade to 1.19.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

c-ares library incorrectly interprets a malformed UDP packet with length 0 as a graceful connection shutdown. An attacker who can intercept and craft responses to DNS queries sent by a target resolver can send these zero-length UDP packets to cause the resolver to prematurely terminate the connection, resulting in denial of service.

MitigationUpgrade c-ares library to version 1.19.1 or later which contains the patch for this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 37= 38
Debian LinuxOperating system
Affected:= 10.0= 11.0
C AresApplication
Affected:< 1.19.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed c-ares library version
    Run 'pkg-config --modversion c-ares' or check the library file with 'ldconfig -p | grep c-ares' and then 'rpm -q' (Red Hat) or 'dpkg -l' (Debian) for the package version
    Affected if The version shown is less than 1.19.1
  2. Check for applications linked against c-ares
    Use 'ldd <binary>' on common DNS-utilizing binaries (such as /usr/bin/curl, /usr/bin/dig, /usr/bin/nslookup) to see if they link to libcares
    Affected if Any of these binaries link to a vulnerable version of c-ares (version < 1.19.1)
  3. Verify c-ares package on Fedora
    Run 'rpm -qa | grep c-ares' to list installed c-ares packages
    Affected if The installed package version is lower than 1.19.1-1 (or the specific fix version for Fedora 37/38)
  4. Verify c-ares package on Debian
    Run 'dpkg -l | grep c-ares' to list installed c-ares packages
    Affected if The installed package version is lower than 1.19.1-1 (or the specific fix version for Debian 10.0/11.0)

A system is affected if any installed version of the c-ares library is below 1.19.1 and that library is used to process DNS queries.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.19.1 or later
Fixed in 1.19.1
Interim mitigation

Upgrade c-ares library to version 1.19.1 or later which contains the patch for this vulnerability.

Recommended fix High confidence

c-ares version 1.19.1

  1. Identify the current c-ares library version installed on the system using package manager (e.g., `dnf info c-ares` on Fedora, `apt show libc-ares` on Debian)
  2. Update the package repository metadata
  3. Upgrade c-ares to version 1.19.1 or later using the system's package manager (e.g., `dnf update c-ares` on Fedora, `apt update && apt install libc-ares` on Debian)
  4. Verify the installed version matches or exceeds 1.19.1
  5. Restart any services that depend on c-ares to ensure the updated library is loaded
Caveat Minimal risk - this is a security bugfix release; upgrading to 1.19.1 should not introduce breaking changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-32067 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data