CVE-2021-1616 Cisco IOS XE Software H.323 Application Level Gateway Bypass Vulnerability

Medium 4.7 Published 23 Sep 2021 Updated 7 Nov 2024

Remote attackers can bypass the H.323 Application Level Gateway in Cisco IOS XE to open unauthorized connections to devices behind NAT.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2021-1616?

CVE-2021-1616 is a medium-severity vulnerability in Cisco Ios Xe, published on 23 Sep 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

A vulnerability in the H.323 application level gateway (ALG) used by the Network Address Translation (NAT) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass the ALG. This vulnerability is due to insufficient data validation of traffic that is traversing the ALG. An attacker could exploit this vulnerability by sending crafted traffic to a targeted device. A successful exploit could allow the attacker to bypass the ALG and open connections that should not be allowed to a remote device located behind the ALG. Note: This vulnerability has been publicly discussed as NAT Slipstreaming.

Weakness: CWE-693

Which versions are affected by CVE-2021-1616?

It affects 1 product.

Products include Cisco Ios Xe.

How do I fix CVE-2021-1616?

No fix has been published for CVE-2021-1616 yet. Limit exposure of the affected software until one is available.

Is CVE-2021-1616 being exploited?

There is no known exploitation of CVE-2021-1616 in the wild and no public exploit code.

All Cisco Ios Xe vulnerabilities

Sources

Also known as GHSA-gh89-2x3x-p7j7.