CVE-2003-0567

What it is

Cisco IOS 11.x and 12.0 through 12.2 allows remote attackers to cause a denial of service (traffic block) by sending a particular sequence of IPv4 packets to an interface on the device, causing the input queue on that interface to be marked as full.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

16.6% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2003-08-18 04:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 22:02 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 16.6% in the next 30 days (EPSS).
• Severity: 7.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2003-08-18 04:00 UTC

Last modified

2026-06-16 22:02 UTC

Exploit probability

16.6% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Cisco iOS 11.0
• Cisco iOS 11.1
• Cisco iOS 11.1aa
• Cisco iOS 11.1ca
• Cisco iOS 11.1cc
• Cisco iOS 11.2
• Cisco iOS 11.2p
• Cisco iOS 11.2sa

Attack profile CVSS 2.0 · 7.8

Attack vector

Network

Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

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