CVE-2020-3255

Cisco Firepower Threat Defense Software Packet Flood Denial of Service Vulnerability

HIGH
7.5
CVSS Score
Published: May 6, 2020 at 04:41 PM UTC
Updated: August 11, 2026 at 07:33 PM UTC
25 products affected across 1 vendorSecure Firewall Threat DefenseASA 5512-x FirmwareASA 5515-x Firmware

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Severity
HIGH7.5
Exploit prediction
EPSS 2%
SSVC
No known exploit

Description

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 high rate of IPv4 or IPv6 traffic through an affected device. This traffic would need to match a configured block action in an access control policy. An exploit could allow the attacker to cause a memory exhaustion condition on the affected device, which would result in a DoS for traffic transiting the device, as well as sluggish performance of the management interface. Once the flood is stopped, performance should return to previous states.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

cisco-asa-5505 (same device)
cisco-asa-5510 (same device)
cisco-asa-5512-x (same device)
cisco-asa-5515-x (same device)
cisco-asa-5520 (same device)
cisco-asa-5525-x (same device)
cisco-asa-5540 (same device)
cisco-asa-5545-x (same device)
cisco-asa-5550 (same device)
cisco-asa-5555-x (same device)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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