CVE-2020-3315: Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass Vulnerability

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-05-06 · updated 2026-08-11
Weakness: CWE-693

Description

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: 15.2(7)e, 16.11.2, 17.3.1
Cisco Firepower Management Center: 2.9.14.4, 2.9.15, 2.9.16
Cisco Firepower Threat Defense Software: before 6.6.0 — fixed in 6.6.0

How to fix

Upgrade to a fixed version: Cisco Firepower Threat Defense Software 6.6.0. Check the vendor advisory for mitigations.

References

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