CVE-2020-3565

Cisco Firepower Threat Defense Software TCP Intercept Bypass Vulnerability

Description

A vulnerability in the TCP Intercept functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured Access Control Policies (including Geolocation) and Service Polices on an affected system. The vulnerability exists because TCP Intercept is invoked when the embryonic connection limit is reached, which can cause the underlying detection engine to process the packet incorrectly. An attacker could exploit this vulnerability by sending a crafted stream of traffic that matches a policy on which TCP Intercept is configured. A successful exploit could allow the attacker to match on an incorrect policy, which could allow the traffic to be forwarded when it should be dropped. In addition, the traffic could incorrectly be dropped.

Categories

5.8
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.20%
Vendor Advisory cisco.com
Affected: Cisco Cisco Firepower Threat Defense Software
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2020-3565?
CVE-2020-3565 has been scored as a medium severity vulnerability.
How to fix CVE-2020-3565?
To fix CVE-2020-3565, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-3565 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-3565 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-3565?
CVE-2020-3565 affects Cisco Cisco Firepower Threat Defense Software.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.