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Debian LinuxOperating system · Debian

CVE-2022-2929

MEDIUM · 6.5 CVSS v3.1 Published 2022-10-07
Fix available
A fix is available. Upgrade to 4.1-esv or later.
See remediation →
70/100
Remediation priority · Elevated
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
In ISC DHCP 1.0 -> 4.4.3, ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16-P1 a system with access to a DHCP server, sending DHCP packets crafted to include fqdn labels longer than 63 bytes, could eventually cause the server to run out of memory.

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

Memory exhaustion vulnerability in ISC DHCP server where specially crafted DHCP packets with FQDN labels exceeding 63 bytes can cause unbounded memory allocation, eventually leading to server exhaustion and denial of service.

MitigationUpdate ISC DHCP to patched version; implement network segmentation and access controls to restrict DHCP packet sources; consider DHCP request rate limiting.

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
Debian LinuxOperating system
Affected:= 10.0
FedoraOperating system
Affected:= 35= 36= 37
DhcpApplication
Affected:>= 1.0.0, < 4.1-esv>= 4.2.0, <= 4.4.3= 4.1-esv

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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. Check if ISC DHCP server is installed
    Run 'dhcpd -v' or 'rpm -q dhcp' (RHEL/Fedora) or 'dpkg -l isc-dhcp-server' (Debian) to find the installed package
    Affected if No ISC DHCP server package is found, then this CVE does not apply
  2. Determine the installed ISC DHCP version
    Run 'dhcpd -v' and note the version number, then compare to affected ranges: < 4.1-esv, >= 4.1-esv to <= 4.4.3, or >= 4.2.0
    Affected if The installed version falls within any of the affected ranges: >= 1.0.0 and < 4.1-esv; = 4.1-esv; or >= 4.2.0 through <= 4.4.3
  3. Verify the DHCP server is network-accessible
    Check if dhcpd is running and listening on network interfaces with 'netstat -tulpn | grep dhcp' or 'ss -tulpn | grep dhcp'
    Affected if The server is exposed to network traffic (not firewalled or isolated), making it reachable to attackers sending malicious DHCP packets
  4. Confirm FQDN or dynamic DNS update configuration is in use
    Inspect /etc/dhcp/dhcpd.conf (or equivalent config path) for 'fqdn', 'ddns-update-style', or client FQDN options that enable FQDN label processing
    Affected if FQDN-related DHCP options are enabled in the configuration, as the vulnerability triggers via oversized FQDN labels

You are affected if ISC DHCP server is running with a version in the affected ranges and the server is network-accessible with FQDN processing enabled.

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 4.1-esv or later
Fixed in 4.1-esv
Interim mitigation

Update ISC DHCP to patched version; implement network segmentation and access controls to restrict DHCP packet sources; consider DHCP request rate limiting.

Recommended fix High confidence

ISC DHCP 4.4.4 or later, or 4.1-ESV-R17 or later; Debian 10 (Buster) and Fedora 35-37 updates via package manager

  1. Update the package repository by running: apt-get update (Debian) or dnf check-update (Fedora)
  2. Install the updated DHCP package: apt-get install isc-dhcp-server (Debian) or dnf update dhcp (Federa)
  3. Alternatively, obtain ISC DHCP 4.4.4 or later from kb.isc.org and compile/install from source
  4. Restart the DHCP server service to apply the update: systemctl restart isc-dhcp-server or systemctl restart dhcpd
  5. Verify the server is running and not experiencing memory leaks with process monitoring tools
Caveat Minor - this is a bug fix; ensure configuration files are backed up before upgrade; test in non-production first

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

Fix this in Debian Linux 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
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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-2022-2929 in production — separate from our analysis above.

No notes yet

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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