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iOSOperating system · Cisco

CVE-2004-1111

MEDIUM · 5.0 CVSS v2.0 Published 2005-01-10
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
Cisco IOS 2.2(18)EW, 12.2(18)EWA, 12.2(14)SZ, 12.2(18)S, 12.2(18)SE, 12.2(18)SV, 12.2(18)SW, and other versions without the "no service dhcp" command, keep undeliverable DHCP packets in the queue instead of dropping them, which allows remote attackers to cause a denial of service (dropped traffic) via multiple undeliverable DHCP packets that exceed the input queue size.

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

In Cisco IOS versions without the 'no service dhcp' command, the DHCP implementation retains undeliverable packets in the input queue instead of discarding them. Attackers can exploit this by flooding the device with undeliverable DHCP packets to fill the queue, causing legitimate traffic to be dropped and resulting in denial of service.

MitigationApply the 'no service dhcp' command to the Cisco IOS configuration to disable the DHCP service and prevent the queue accumulation behavior, or implement proper input queue rate limiting as a compensating control if DHCP functionality is required.

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
iOSOperating system
Affected:= 12.2\(14\)sz= 12.2\(18\)ew= 12.2\(18\)ewa= 12.2\(18\)s= 12.2\(18\)se= 12.2\(18\)sv= 12.2\(18\)sw= 12.2\(20\)ew
Multiservice Platform 2650Hardware / appliance
Affected:all versions
Multiservice Platform 2650xmHardware / appliance
Affected:all versions
Multiservice Platform 2651Hardware / appliance
Affected:all versions
Multiservice Platform 2651xmHardware / appliance
Affected:all versions
7200 RouterHardware / appliance
Affected:all versions
7300 RouterHardware / appliance
Affected:all versions
7500 RouterHardware / appliance
Affected:all versions

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. Verify if DHCP service is enabled on the device
    Examine the running configuration with 'show running-config | include service dhcp'. Look for the absence of 'no service dhcp' command, which means DHCP is enabled and the device is potentially vulnerable.
    Affected if The configuration does not contain 'no service dhcp' (DHCP service is enabled)
  2. Identify the Cisco device model
    Execute 'show version' and locate the hardware model information (e.g., Cisco 7200 Router, Cisco 7500 Router, Cisco Multiservice Platform 2650).
    Affected if The device is a Cisco 7200 Router, Cisco 7300 Router, Cisco 7500 Router, or any Cisco Multiservice Platform 2650/2650xm/2651/2651xm (all versions of these platforms are affected when DHCP is enabled)
  3. Identify the IOS version if the device is a Cisco IOS platform
    Execute 'show version' and locate the IOS release string (e.g., 12.2(14)sz, 12.2(18)ew).
    Affected if The IOS version matches exactly: 12.2(14)sz, 12.2(18)ew, 12.2(18)ewa, 12.2(18)s, 12.2(18)se, 12.2(18)sv, 12.2(18)sw, or 12.2(20)ew AND DHCP is enabled
  4. Check input queue status for potential DoS indicators
    Execute 'show interface' commands to view input queue statistics. Look for high packet counts in the input queue that could indicate queue exhaustion from malicious traffic.
    Affected if Input queues show unusually high packet counts or drops while DHCP traffic is present on the network

The device is affected if it is one of the listed hardware platforms (all versions) or IOS versions (exact matches) AND the 'no service dhcp' command is not configured, meaning DHCP service is 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.

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

Apply the 'no service dhcp' command to the Cisco IOS configuration to disable the DHCP service and prevent the queue accumulation behavior, or implement proper input queue rate limiting as a compensating control if DHCP functionality is required.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,820
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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-2004-1111 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