CVE-2019-1740 Cisco IOS and IOS XE Software Network-Based Application Recognition Denial of Service Vulnerabilities

High 8.6 Published 27 Mar 2019 Updated 19 Nov 2024

Remote attackers can cause Cisco IOS devices to reload by sending crafted DNS packets if NBAR is enabled, resulting in a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2019-1740?

CVE-2019-1740 is a high-severity denial of service vulnerability in Cisco Ios, published on 27 Mar 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the Network-Based Application Recognition (NBAR) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability are due to a parsing issue on DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through routers that are running an affected version and have NBAR enabled. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.

Weakness: CWE-20

Which versions are affected by CVE-2019-1740?

It affects 2 products.

Products include Cisco Ios, Cisco Ios Xe.

How do I fix CVE-2019-1740?

No fix has been published for CVE-2019-1740 yet. Limit exposure of the affected software until one is available.

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-2019-1740 being exploited?

There is no known exploitation of CVE-2019-1740 in the wild and no public exploit code.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-454m-cf77-vmj9.