CVE-2020-3315: Cisco IOS

Medium severity, CVSS 5.3. EPSS: 2.2% chance of exploitation in the next 30 days.

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured file policies on an affected system. The vulnerability is due to errors in how the Snort detection engine handles specific HTTP responses. An attacker could exploit this vulnerability by sending crafted HTTP packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured file policies and deliver a malicious payload to the protected network.

Affected products

• Cisco IOS: version 15.2(7)e only; version 16.11.2 only; version 17.3.1 only
• Cisco Secure Firewall Management Center: version 2.9.14.4 only; version 2.9.15 only; version 2.9.16 only
• Cisco Secure Firewall Threat Defense: before 6.6.0 (fixed in 6.6.0)

Published 2020-05-06. Last modified 2026-08-11.