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DhcpApplication · Isc

CVE-2010-3616

MEDIUM · 5.0 CVSS v2.0 Published 2010-12-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
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
ISC DHCP server 4.2 before 4.2.0-P2, when configured to use failover partnerships, allows remote attackers to cause a denial of service (communications-interrupted state and DHCP client service loss) by connecting to a port that is only intended for a failover peer, as demonstrated by a Nagios check_tcp process check to TCP port 520.

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

ISC DHCP server 4.2 before 4.2.0-P2 contains a flaw in its failover mechanism. When configured with failover partnerships, the server listens on TCP port 520 for peer communications. An attacker connecting to this port causes the server to enter a communications-interrupted state, disrupting DHCP service to all clients.

MitigationUpgrade to ISC DHCP 4.2.0-P2 or later. Alternatively, firewall the failover port (520) to restrict access to only trusted failover peer IP addresses.

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
DhcpApplication
Affected:= 4.2.0

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
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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 ISC DHCP version
    Run 'dhcpd -v' or 'dhcpd --version' to get the installed version of the ISC DHCP server
    Affected if Version is 4.2.0 through 4.2.0-P1 (versions before 4.2.0-P2)
  2. Check for failover configuration
    Inspect the DHCP server configuration file (commonly /etc/dhcpd.conf or /etc/dhcp/dhcpd.conf) for 'failover' or 'peer' statements that define a failover partnership
    Affected if Failover peer configuration is present in the config file
  3. Verify failover port is listening
    Run 'netstat -tlnp | grep 520' or 'ss -tlnp | grep 520' to check if TCP port 520 is open and listening
    Affected if Port 520 is open and listening, indicating the failover mechanism is active

If the installed version is 4.2.0 before 4.2.0-P2, failover is configured, and port 520 is listening, the server is vulnerable to denial of service via unauthorized connections to the failover port.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to ISC DHCP 4.2.0-P2 or later. Alternatively, firewall the failover port (520) to restrict access to only trusted failover peer IP addresses.

Fix this in Dhcp Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2010-3616 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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