Firepower Threat Defense
CVE-2020-3577
HIGH
Severity by source
AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Lifecycle Timeline
1DescriptionNVD
A vulnerability in the ingress packet processing path of Cisco Firepower Threat Defense (FTD) Software for interfaces that are configured either as Inline Pair or in Passive mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation when Ethernet frames are processed. An attacker could exploit this vulnerability by sending malicious Ethernet frames through an affected device. A successful exploit could allow the attacker do either of the following: Fill the /ngfw partition on the device: A full /ngfw partition could result in administrators being unable to log in to the device (including logging in through the console port) or the device being unable to boot up correctly. Note: Manual intervention is required to recover from this situation. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition. Cause a process crash: The process crash would cause the device to reload. No manual intervention is necessary to recover the device after the reload.
AnalysisAI
A vulnerability in the ingress packet processing path of Cisco Firepower Threat Defense (FTD) Software for interfaces that are configured either as Inline Pair or in Passive mode could allow an. Rated high severity (CVSS 7.4), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified under CWE-20. A vulnerability in the ingress packet processing path of Cisco Firepower Threat Defense (FTD) Software for interfaces that are configured either as Inline Pair or in Passive mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation when Ethernet frames are processed. An attacker could exploit this vulnerability by sending malicious Ethernet frames through an affected device. A successful exploit could allow the attacker do either of the following: Fill the /ngfw partition on the device: A full /ngfw partition could result in administrators being unable to log in to the device (including logging in through the console port) or the device being unable to boot up correctly. Note: Manual intervention is required to recover from this situation. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition. Cause a process crash: The process crash would cause the device to reload. No manual intervention is necessary to recover the device after the reload. Affected products include: Cisco Firepower Threat Defense.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
More in Firepower Threat Defense
View allUpdate: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure ASA Softwar
A vulnerability in the Secure Sockets Layer (SSL) VPN functionality of the Cisco Adaptive Security Appliance (ASA) Softw
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Th
A vulnerability in the web services interface for remote access VPN features of Cisco Adaptive Security Appliance (ASA)
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Th
A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remo
Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Fir
A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower
Multiple vulnerabilities in the multi-instance feature of Cisco Firepower Threat Defense (FTD) Software could allow an a
A vulnerability in the Remote Access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower
A vulnerability in the TLS cryptography functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Fire
A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat D
Same weakness CWE-20 – Improper Input Validation
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today