dbcve.org
iOSOperating system · Cisco

CVE-2003-0100

HIGH · 7.5 CVSS v2.0 Published 2003-03-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
Buffer overflow in Cisco IOS 11.2.x to 12.0.x allows remote attackers to cause a denial of service and possibly execute commands via a large number of OSPF neighbor announcements.

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

Buffer overflow vulnerability in Cisco IOS versions 11.2.x through 12.0.x allows remote attackers to send malformed OSPF neighbor announcements, triggering a buffer overflow that can cause device crash (denial of service) or potentially allow arbitrary command execution.

MitigationUpgrade affected Cisco IOS devices to a patched version beyond 12.0.x; restrict OSPF adjacency to trusted neighbors using authentication and access control lists to reduce attack surface.

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:= 11.1= 11.1\(7\)aa= 11.1\(7\)ca= 11.1\(9\)ia= 11.1\(13\)= 11.1\(13\)aa= 11.1\(13\)ca= 11.1\(13\)ia= 11.1\(15\)aa= 11.1\(15\)ca= 11.1\(15\)ia= 11.1\(16\)aa

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
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/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 Cisco IOS version
    Run 'show version' on the device CLI and locate the IOS release line (typically shows as 'Version 12.0(5)' or similar)
    Affected if The installed version falls within 11.2.x through 12.0.x, or matches any of these specific versions: 11.1, 11.1(7)aa, 11.1(7)ca, 11.1(9)ia, 11.1(13), 11.1(13)aa, 11.1(13)ca, 11.1(13)ia, 11.1(15)aa, 11.1(15)ca, 11.1(15)ia, 11.1(16)aa
  2. Confirm OSPF is enabled
    Run 'show ip ospf' or 'show running-config | include router ospf' to see if OSPF routing is configured
    Affected if OSPF is actively configured and running on the device
  3. Check for OSPF neighbors
    Run 'show ip ospf neighbor' to list OSPF neighbor adjacencies
    Affected if Any OSPF neighbors are present, indicating the device is participating in OSPF routing and could receive malformed neighbor announcements
  4. Verify OSPF interface exposure
    Run 'show ip ospf interface' to see which interfaces have OSPF enabled
    Affected if OSPF is enabled on interfaces accessible to untrusted network segments (not behind ACLs or on management-only interfaces)

The device is affected if it runs a Cisco IOS version between 11.2.x and 12.0.x (or the specific 11.1.x versions listed) AND has OSPF enabled and exposed to network neighbors.

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 affected Cisco IOS devices to a patched version beyond 12.0.x; restrict OSPF adjacency to trusted neighbors using authentication and access control lists to reduce attack surface.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2003-0100 — 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-2003-0100 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