CVE-2020-3373

highpriority · track · 35EPSS 0.020 · 80 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.98% (80th) EPSS

CVSS 7.8 · high

Is it mine?

47 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 IP fragment-handling implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak on an affected device. This memory leak could prevent traffic from being processed through the device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper error handling when specific failures occur during IP fragment reassembly. An attacker could exploit this vulnerability by sending crafted, fragmented IP traffic to a targeted device. A successful exploit could allow the attacker to continuously consume memory on the affected device and eventually impact traffic, resulting in a DoS condition. The device could require a manual reboot to recover from the DoS condition. Note: This vulnerability applies to both IP Version 4 (IPv4) and IP Version 6 (IPv6) traffic.

remediations

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

A vendor fix is available.

FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.2 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 Adaptive Security Appliance (ASA) Software 9.12.4.2 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 Adaptive Security Appliance (ASA) Software 9.12.4.2 when installed on Cisco Adaptive Security Virtual Appliance (ASAv)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.2 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.2 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.2 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.14.1.15 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 Adaptive Security Appliance (ASA) Software 9.14.1.15 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 Adaptive Security Appliance (ASA) Software 9.14.1.15 when installed on Cisco Adaptive Security Virtual Appliance (ASAv)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.14.1.15 when installed on Cisco Firepower 1000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.14.1.15 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.14.1.15 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.14.1.15 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.22 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 Adaptive Security Appliance (ASA) Software 9.8.4.22 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 Adaptive Security Appliance (ASA) Software 9.8.4.22 when installed on Cisco Adaptive Security Virtual Appliance (ASAv)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.22 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.22 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.22 when installed on Cisco Firepower 9000 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.25 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 Adaptive Security Appliance (ASA) Software 9.8.4.25 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 Adaptive Security Appliance (ASA) Software 9.8.4.25 when installed on Cisco Adaptive Security Virtual Appliance (ASAv)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.25 when installed on Cisco Firepower 2100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.25 when installed on Cisco Firepower 4100 Seriescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.8.4.25 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 6.6.0.1 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 6.6.0.1 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 6.6.0.1 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 6.6.0.1 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 6.6.0.1 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 6.6.0.1 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 6.6.0.1 when installed on Cisco Secure Firewall Threat Defense Virtualcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

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

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

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4

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

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US

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-401USprimaryCWE-400USCWE-400USCWE-401US

affected products (47)

Products and version ranges known to be affected.

showing 20 of 47

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-asaftd-frag-memleak-mCtqdP9nCisco Adaptive Security Appliance Software and Firepower Threat Defense Software IP Fragment Memory Leak Vulnerability2020-10-21csaf · cisco_csafUS
Update from October 22nd, 2020: Cisco has become aware of a new Cisco Adaptive Security Appliance vulnerability that could affect the fixed releases recommended for code trains 9.13 and 9.14 in the Fixed Software ["#fs"] section of this advisory. See the Cisco Adaptive Security Appliance Software SSL/TLS Denial of Service Vulnerability ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-dos-7uZWwSEy"] for additional information. A vulnerability in the IP fragment-handling implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak on an affected device. This memory leak could prevent traffic from being processed through the device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper error handling when specific failures occur during IP fragment reassembly. An attacker could exploit this vulnerability by sending crafted, fragmented IP traffic to a targeted device. A successful exploit could allow the attacker to continuously consume memory on the affected device and eventually impact traffic, resulting in a DoS condition. The device could require a manual reboot to recover from the DoS condition. Note: This vulnerability applies to both IP Version 4 (IPv4) and IP Version 6 (IPv6) traffic. 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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references (8)

External citations — patches, advisories, analysis.

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