CVE-2021-1446 Cisco IOS XE Software DNS NAT Protocol Application Layer Gateway Denial of Service Vulnerability
Remote attackers can cause Cisco IOS XE devices to reload by sending crafted DNS packets through NAT, 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-2021-1446?
CVE-2021-1446 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 24 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the DNS application layer gateway (ALG) functionality used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a logic error that occurs when an affected device inspects certain DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through an affected device that is performing NAT for DNS packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition on an affected device. The vulnerability can be exploited only by traffic that is sent through an affected device via IPv4 packets. The vulnerability cannot be exploited via IPv6 traffic.
Weakness: CWE-754
Which versions are affected by CVE-2021-1446?
It affects 1 product.
Products include Cisco Ios Xe.
How do I fix CVE-2021-1446?
No fix has been published for CVE-2021-1446 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-2021-1446 being exploited?
There is no known exploitation of CVE-2021-1446 in the wild and no public exploit code.
Other vulnerabilities in Cisco Ios Xe
- CVE-2023-20198 Cisco IOS XE Web UI Privilege Escalation
- CVE-2018-0151 Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution
- CVE-2023-20273 Cisco IOS XE Web UI Command Injection
- CVE-2025-20188 Hardcoded credentials in Cisco IOS XE Software
- CVE-2021-34770 Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability
Sources
Also known as GHSA-m3m6-h5x2-mhf5.