Cisco Snort 3 VBA Crash DoS via Unauth Remote Attacker
CVE-2026-20054 Published on March 4, 2026

Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Infinite Loop Denial of Service Vulnerability
Multiple Cisco products are affected by a vulnerability in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.  This vulnerability is due to improper error checking when decompressing VBA data. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to enter an infinite loop, causing a DoS condition.

NVD

Vulnerability Analysis

CVE-2026-20054 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Weakness Type

What is an Infinite Loop Vulnerability?

The program contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. If the loop can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory.

CVE-2026-20054 has been classified to as an Infinite Loop vulnerability or weakness.


Products Associated with CVE-2026-20054

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Cisco Cyber Vision
 

Affected Versions

Cisco Cyber Vision: Cisco Secure Firewall Threat Defense (FTD) Software: Cisco UTD SNORT IPS Engine Software:

Exploit Probability

EPSS
0.09%
Percentile
26.13%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.