CVE-2023-20072

What it is

A vulnerability in the fragmentation handling code of tunnel protocol packets in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected system to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to the improper handling of large fragmented tunnel protocol packets. One example of a tunnel protocol is Generic Routing Encapsulation (GRE). An attacker could exploit this vulnerability by sending crafted fragmented packets to an affected system. A successful exploit could allow the attacker to cause the affected system to reload, resulting in a DoS condition. Note: Only traffic directed to the affected system can be used to exploit this vulnerability.

At a glance

Exploitability

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

Exploit odds

1.0% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2023-03-23 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 05:29 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.0% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-03-23 17:15 UTC

Last modified

2026-06-17 05:29 UTC

Exploit probability

1.0% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Cisco iOS Xe 17.9.1
• Cisco iOS Xe 17.9.1a
• Cisco iOS Xe 17.9.1w

Attack profile CVSS 3.1 · 8.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

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-2023-20072.md and follow it. Check whether this project is affected by CVE-2023-20072. 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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