CVE-2017-12231 Cisco IOS Software Network Address Translation Denial-of-Service

Exploited in the wild High 7.5 Published 28 Sep 2017 Updated 14 Jan 2026

Remote attackers can crash Cisco IOS devices by sending crafted H.323 RAS packets, causing a denial of service.

Exploited in the wild: Since 3 Mar 2022
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2017-12231?

CVE-2017-12231 is a high-severity denial of service vulnerability in Cisco Ios, published on 28 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217.

Weakness: CWE-399

Which versions are affected by CVE-2017-12231?

It affects 1 product.

Products include Cisco Ios.

How do I fix CVE-2017-12231?

No fix has been published for CVE-2017-12231 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Mar 2022.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2017-12231 being exploited?

Yes. Attackers have exploited CVE-2017-12231 in the wild since at least 3 Mar 2022.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-83rp-43rf-7hmv.