CVE-2021-34698 Cisco Web Security Appliance Proxy Service Denial of Service Vulnerability

High 8.6 Published 6 Oct 2021 Updated 7 Nov 2024

Unauthenticated remote attackers can cause a denial of service on Cisco Web Security Appliances by exhausting system memory via numerous HTTPS connections.

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-2021-34698?

CVE-2021-34698 is a high-severity denial of service vulnerability in Cisco Asyncos, published on 6 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the proxy service of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to exhaust system memory and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management in the proxy service of an affected device. An attacker could exploit this vulnerability by establishing a large number of HTTPS connections to the affected device. A successful exploit could allow the attacker to cause the system to stop processing new connections, which could result in a DoS condition. Note: Manual intervention may be required to recover from this situation.

Weakness: CWE-401

Which versions are affected by CVE-2021-34698?

It affects 1 product.

Products include Cisco Asyncos.

How do I fix CVE-2021-34698?

No fix has been published for CVE-2021-34698 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-2021-34698 being exploited?

There is no known exploitation of CVE-2021-34698 in the wild and no public exploit code.

All Cisco Asyncos vulnerabilities

Sources

Also known as GHSA-vj66-rqm3-j78p.