dbcve.org
FreeBSDOperating system

CVE-2000-0440

MEDIUM · 5.0 CVSS v2.0 Published 2000-05-01
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
NetBSD 1.4.2 and earlier allows remote attackers to cause a denial of service by sending a packet with an unaligned IP timestamp option.

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

NetBSD 1.4.2 and earlier contains a kernel-level vulnerability in IP packet handling where processing an unaligned IP timestamp option triggers a denial of service condition. The vulnerability is remotely exploitable via specially crafted packets.

MitigationUpgrade NetBSD to version 1.4.3 or later, or apply the vendor patch that corrects IP timestamp option alignment handling in the kernel network stack.

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
FreeBSDOperating system
Affected:= 3.4= 4.0= 5.0
NetbsdOperating system
Affected:= 1.4.1= 1.4.2

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 the installed operating system version
    Run 'uname -a' to display system information, or check /etc/motd or /var/run/dmesg.boot for version details
    Affected if The displayed version is FreeBSD 3.4, 4.0, or 5.0, or NetBSD 1.4.1 or 1.4.2
  2. Confirm the system is a BSD derivative
    Check the kernel name from uname output or examine /etc/os-release if available
    Affected if The operating system is identified as FreeBSD or NetBSD and matches the version criteria from step 1
  3. Verify IP networking is enabled
    Check if the network interface is configured by running 'ifconfig -a' to list network interfaces and their status
    Affected if The system has active network interfaces configured with IP addresses, indicating the IP stack is in use
  4. Confirm kernel is processing IP traffic
    Use 'netstat -i' or 'netstat -s' to display network statistics and verify IP protocol activity
    Affected if IP protocol statistics are present, showing the kernel is actively processing IP packets

A system is affected if it runs FreeBSD 3.4, 4.0, or 5.0 or NetBSD 1.4.1 or 1.4.2 with an active IP network stack, since the vulnerability lies in kernel-level IP timestamp option handling.

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 NetBSD to version 1.4.3 or later, or apply the vendor patch that corrects IP timestamp option alignment handling in the kernel network stack.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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Scan for this in your stack

Free · runs locally
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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-2000-0440 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