CVE-2006-4650

What it is

Cisco IOS 12.0, 12.1, and 12.2, when GRE IP tunneling is used and the RFC2784 compliance fixes are missing, does not verify the offset field of a GRE packet during decapsulation, which leads to an integer overflow that references data from incorrect memory locations, which allows remote attackers to inject crafted packets into the routing queue, possibly bypassing intended router ACLs.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.2% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2006-09-09 00:04 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 22:29 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.2% in the next 30 days (EPSS).
• Severity: 2.6 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2006-09-09 00:04 UTC

Last modified

2026-06-16 22:29 UTC

Exploit probability

3.2% · EPSS, next 30 days

Record status

Modified

Affected

• Cisco iOS 12.0
• Cisco iOS 12.1
• Cisco iOS 12.2

Attack profile CVSS 2.0 · 2.6

Attack vector

Network

Complexity

High

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

None

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.

Read https://cve-list.com/agent/cve/CVE-2006-4650.md and follow it. Check whether this project is affected by CVE-2006-4650. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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