Cybersecurity professionals consider CVE-2020-3373 an immediate threat requiring urgent mitigation.
Status: Modified
Last updated: 🕢 11 Aug 2026, 19:33 UTC
Originally published on: 🕖 21 Oct 2020, 19:15 UTC
Time between publication and last update: 2120 days
CVSS Release: version 3
psirt@cisco.com
Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVE-2020-3373: 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.
The exploitability of CVE-2020-3373 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
With low attack complexity and no required privileges, CVE-2020-3373 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2020-3373, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2020-3373, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.16% (probability of exploit)
EPSS Percentile: 53.91%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 46.09% of others.
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