Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IP Fragment Memory Leak Vulnerability

published 2020-10-21 6y ago modified 2026-08-11 2mo ago also EUVD-2020-24644

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.0%; EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits: 0; none known

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.

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CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: last yr. (2024-11-13)

Exploit prediction

1.98% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	2.0	7.8	AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

Cisco Cisco Adaptive Security Appliance (ASA) Software

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-401 Missing Release of Memory after Effective Lifetime

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-frag-memleak-mCtqdP9n
vendor-advisory

Sources

CVE List CVE-2020-3373
NVD CVE-2020-3373

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