dbcve.org
Zabbix AgentApplication · Zabbix

CVE-2023-32726

HIGH · 8.1 CVSS v3.1 Published 2023-12-18
Fix available
A fix is available. Upgrade to after 6.4.8 or later.
See remediation →
90/100
Remediation priority · Urgent
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
The vulnerability is caused by improper check for check if RDLENGTH does not overflow the buffer in response from DNS server.

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 · moderate confidence

The vulnerability exists in DNS response parsing where the RDLENGTH field is not properly validated against available buffer space. This improper bounds check can allow a crafted DNS response with a maliciously large RDLENGTH value to overflow the receive buffer, potentially leading to remote code execution or denial of service.

MitigationApply vendor patches that implement proper validation of RDLENGTH against buffer boundaries before processing DNS resource records. Until patched, limit exposure by restricting DNS resolver access to trusted networks.

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
Zabbix AgentApplication
Affected:>= 5.0.0, <= 5.0.39>= 6.0.0, <= 6.0.23>= 6.4.0, <= 6.4.8= 7.0.0

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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. Verify Zabbix Agent installation and executable
    Run 'zabbix_agentd --version' or check for the binary at common paths like /usr/sbin/zabbix_agentd or C:\Program Files\Zabbix\zabbix_agentd.exe
    Affected if Zabbix Agent is not installed on the system
  2. Identify installed Zabbix Agent version
    Execute 'zabbix_agentd --version' or check the package manager output (dpkg -l zabbix-agent, rpm -qi zabbix-agent)
    Affected if The installed version falls within 5.0.0-5.0.39, 6.0.0-6.0.23, 6.4.0-6.4.8, or equals 7.0.0
  3. Confirm DNS monitoring is configured
    Inspect the Zabbix Agent configuration file (zabbix_agentd.conf) for 'Hostname', 'Server', or 'ServerActive' parameters, and review Zabbix UI/API for active items of type 'DNS' that the agent will execute
    Affected if The agent performs DNS lookups as part of monitoring tasks, enabling it to receive and parse DNS responses from arbitrary servers
  4. Check agent network binding and exposure
    Review the 'ListenIP' and 'ListenPort' settings in zabbix_agentd.conf, and examine firewall rules or network segmentation protecting the agent
    Affected if The agent listens on accessible network interfaces or communicates with untrusted DNS resolvers, allowing malicious DNS responses to reach the agent

You are affected if Zabbix Agent is installed with a version within the affected ranges AND the agent is configured to perform DNS queries, making it susceptible to crafted DNS responses with oversized RDLENGTH values.

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 a release after 6.4.8
Interim mitigation

Apply vendor patches that implement proper validation of RDLENGTH against buffer boundaries before processing DNS resource records. Until patched, limit exposure by restricting DNS resolver access to trusted networks.

Recommended fix High confidence

Zabbix Agent 5.0.40, 6.0.24, 6.4.9, or 7.0.1 (depending on your major version branch)

  1. 1. Identify the currently installed Zabbix Agent version using: `zabbix_agentd --version` or `rpm -qa | grep zabbix`
  2. 2. For Debian/Ubuntu: Update package list with `apt update` and upgrade Zabbix Agent with `apt install zabbix-agent`
  3. 3. For RHEL/CentOS/Fedora: Use `dnf check-update` or `yum check-update` to see available updates, then `dnf update zabbix-agent` or `yum update zabbix-agent`
  4. 4. If using official Zabbix packages, ensure the Zabbix repository is configured for the target version
  5. 5. After upgrade, restart the Zabbix Agent service: `systemctl restart zabbix-agent` or `service zabbix-agent restart`
  6. 6. Verify the new version is installed: `zabbix_agentd --version`
Caveat Standard minor version upgrades typically retain configuration; back up /etc/zabbix/zabbix_agentd.conf before upgrading as a precaution

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

Fix this in Zabbix Agent Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-32726 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-32726 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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