CVE-2025-20183 Cisco Secure Web Appliance Range Request Bypass Vulnerability

Medium 5.8 Published 5 Feb 2025 Updated 5 Feb 2025

An unauthenticated remote attacker can bypass antivirus scanning via crafted range requests, allowing malware downloads on endpoints.

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-2025-20183?

CVE-2025-20183 is a medium-severity vulnerability in Cisco Asyncos, published on 5 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in a policy-based Cisco Application Visibility and Control (AVC) implementation of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to evade the antivirus scanner and download a malicious file onto an endpoint.  The vulnerability is due to improper handling of a crafted range request header. An attacker could exploit this vulnerability by sending an HTTP request with a crafted range request header through the affected device. A successful exploit could allow the attacker to evade the antivirus scanner and download malware onto the endpoint without detection by Cisco Secure Web Appliance.

Weakness: CWE-20

Which versions are affected by CVE-2025-20183?

It affects 1 product.

Products include Cisco Asyncos.

How do I fix CVE-2025-20183?

No fix has been published for CVE-2025-20183 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-20183 being exploited?

There is no known exploitation of CVE-2025-20183 in the wild and no public exploit code.

All Cisco Asyncos vulnerabilities

Sources

Also known as GHSA-6fqv-9m7r-mcwr.