CVE-2020-3563

highpriority · track · 34EPSS 0.014 · 73 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.43% (73rd) EPSS

CVSS 7.8 · high

Is it mine?

76 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

A vulnerability in the packet processing functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to inefficient memory management. An attacker could exploit this vulnerability by sending a large number of TCP packets to a specific port on an affected device. A successful exploit could allow the attacker to exhaust system memory, which could cause the device to reload unexpectedly. No manual intervention is needed to recover the device after it has reloaded.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco ASA 5500-X Series Firewallscisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

Technical severity, 0–10. One row per scoring source.

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.07.8highAV:N/AC:L/Au:N/C:N/I:N/A:Cprimary · NVD / NIST USexploitability 10 · impact 6.9

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 4

v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4

v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US

v3.18.6highAV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USprimaryCWE-400US

affected products (76)

Products and version ranges known to be affected.

showing 20 of 76

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-ftd-tcp-dos-GDcZDqAfCisco Firepower Threat Defense Software TCP Flood Denial of Service Vulnerability2020-10-21csaf · cisco_csafUS
A vulnerability in the packet processing functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to inefficient memory management. An attacker could exploit this vulnerability by sending a large number of TCP packets to a specific port on an affected device. A successful exploit could allow the attacker to exhaust system memory, which could cause the device to reload unexpectedly. No manual intervention is needed to recover the device after it has reloaded. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the October 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 17 Cisco Security Advisories that describe 17 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: October 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74302"].

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisco_csaf NVD CVE.org MITRE

published 2020-10-21modified 2026-08-11

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+9608 more

references (6)

External citations — patches, advisories, analysis.

scry

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