---
id: CVE-2026-20053
title: "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.\r\n\r\nThis vulnerability is due to improper range checki…"
summary: "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.\r\n\r\nThis vulnerability is due to improper range checki…"
severity: medium
cvss: 5.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'
cwe:
  - CWE-122
vendor: cisco
product: snort
affected:
  - 'snort >= 3.0.0-233, < 3.9.3.0'
  - cyber_vision = 3.0.0
  - cyber_vision = 3.0.1
  - cyber_vision = 3.0.2
  - cyber_vision = 3.0.3
  - cyber_vision = 3.0.4
  - cyber_vision = 3.0.5
  - cyber_vision = 3.0.6
  - cyber_vision = 3.1.0
  - cyber_vision = 3.1.1
  - cyber_vision = 3.1.2
  - cyber_vision = 3.2.0
  - cyber_vision = 3.2.1
  - cyber_vision = 3.2.2
  - cyber_vision = 3.2.3
  - cyber_vision = 3.2.4
  - cyber_vision = 4.0.0
  - cyber_vision = 4.0.1
  - cyber_vision = 4.0.2
  - cyber_vision = 4.0.3
  - cyber_vision = 4.1.0
  - cyber_vision = 4.1.1
  - cyber_vision = 4.1.2
  - cyber_vision = 4.1.3
  - cyber_vision = 4.1.4
  - cyber_vision = 4.1.5
  - cyber_vision = 4.1.6
  - cyber_vision = 4.1.7
  - cyber_vision = 4.2.0
  - cyber_vision = 4.2.1
  - cyber_vision = 4.2.2
  - cyber_vision = 4.2.3
  - cyber_vision = 4.2.4
  - cyber_vision = 4.2.6
  - cyber_vision = 4.3.0
  - cyber_vision = 4.3.1
  - cyber_vision = 4.3.2
  - cyber_vision = 4.3.3
  - cyber_vision = 4.4.0
  - cyber_vision = 4.4.1
  - cyber_vision = 4.4.2
  - cyber_vision = 4.4.3
  - cyber_vision = 5.0.0
  - cyber_vision = 5.0.1
  - cyber_vision = 5.0.2
  - cyber_vision = 5.1.0
  - cyber_vision = 5.1.1
  - cyber_vision = 5.1.2
  - cyber_vision = 5.1.3
  - cyber_vision = 5.2.0
  - cyber_vision = 5.2.1
  - cyber_vision = 5.3.0
  - cyber_vision = 5.3.1
  - cyber_vision = 5.3.2
  - secure_firewall_threat_defense = 7.2.0
  - secure_firewall_threat_defense = 7.2.0.1
  - secure_firewall_threat_defense = 7.2.1
  - secure_firewall_threat_defense = 7.2.2
  - secure_firewall_threat_defense = 7.2.3
  - secure_firewall_threat_defense = 7.2.4
  - secure_firewall_threat_defense = 7.2.4.1
  - secure_firewall_threat_defense = 7.2.5
  - secure_firewall_threat_defense = 7.2.5.1
  - secure_firewall_threat_defense = 7.2.5.2
  - secure_firewall_threat_defense = 7.2.6
  - secure_firewall_threat_defense = 7.2.7
  - secure_firewall_threat_defense = 7.2.8
  - secure_firewall_threat_defense = 7.2.8.1
  - secure_firewall_threat_defense = 7.2.9
  - secure_firewall_threat_defense = 7.2.10
  - secure_firewall_threat_defense = 7.2.10.2
  - secure_firewall_threat_defense = 7.3.0
  - secure_firewall_threat_defense = 7.3.1
  - secure_firewall_threat_defense = 7.3.1.1
  - secure_firewall_threat_defense = 7.3.1.2
  - secure_firewall_threat_defense = 7.4.0
  - secure_firewall_threat_defense = 7.4.1
  - secure_firewall_threat_defense = 7.4.1.1
  - secure_firewall_threat_defense = 7.4.2
  - secure_firewall_threat_defense = 7.4.2.1
  - secure_firewall_threat_defense = 7.4.2.2
  - secure_firewall_threat_defense = 7.4.2.3
  - secure_firewall_threat_defense = 7.4.2.4
  - secure_firewall_threat_defense = 7.4.3
  - secure_firewall_threat_defense = 7.6.0
  - secure_firewall_threat_defense = 7.6.1
  - secure_firewall_threat_defense = 7.6.2
  - secure_firewall_threat_defense = 7.6.2.1
  - secure_firewall_threat_defense = 7.7.0
  - secure_firewall_threat_defense = 7.7.10
  - secure_firewall_threat_defense = 7.7.10.1
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.9.4
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.9.5e
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.1a
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.2
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.3
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.3a
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4a
  - unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4b
patched:
  - snort 3.9.3.0
published: '2026-03-04'
updated: '2026-08-20'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20053'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort3-vbavuls-96UcVVed
    label: psirt@cisco.com
tags:
  - nvd
epss: 0.00414
epssPercentile: 0.32897
ingestedAt: '2026-08-20T17:59:04.119Z'
---

## Overview

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 range checking when decompressing VBA data, which is user controlled. 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 an overflow of heap data, which could cause a DoS condition.

## Affected

- `snort >= 3.0.0-233, < 3.9.3.0`
- `cyber_vision = 3.0.0`
- `cyber_vision = 3.0.1`
- `cyber_vision = 3.0.2`
- `cyber_vision = 3.0.3`
- `cyber_vision = 3.0.4`
- `cyber_vision = 3.0.5`
- `cyber_vision = 3.0.6`
- `cyber_vision = 3.1.0`
- `cyber_vision = 3.1.1`
- `cyber_vision = 3.1.2`
- `cyber_vision = 3.2.0`
- `cyber_vision = 3.2.1`
- `cyber_vision = 3.2.2`
- `cyber_vision = 3.2.3`
- `cyber_vision = 3.2.4`
- `cyber_vision = 4.0.0`
- `cyber_vision = 4.0.1`
- `cyber_vision = 4.0.2`
- `cyber_vision = 4.0.3`
- `cyber_vision = 4.1.0`
- `cyber_vision = 4.1.1`
- `cyber_vision = 4.1.2`
- `cyber_vision = 4.1.3`
- `cyber_vision = 4.1.4`
- `cyber_vision = 4.1.5`
- `cyber_vision = 4.1.6`
- `cyber_vision = 4.1.7`
- `cyber_vision = 4.2.0`
- `cyber_vision = 4.2.1`
- `cyber_vision = 4.2.2`
- `cyber_vision = 4.2.3`
- `cyber_vision = 4.2.4`
- `cyber_vision = 4.2.6`
- `cyber_vision = 4.3.0`
- `cyber_vision = 4.3.1`
- `cyber_vision = 4.3.2`
- `cyber_vision = 4.3.3`
- `cyber_vision = 4.4.0`
- `cyber_vision = 4.4.1`
- `cyber_vision = 4.4.2`
- `cyber_vision = 4.4.3`
- `cyber_vision = 5.0.0`
- `cyber_vision = 5.0.1`
- `cyber_vision = 5.0.2`
- `cyber_vision = 5.1.0`
- `cyber_vision = 5.1.1`
- `cyber_vision = 5.1.2`
- `cyber_vision = 5.1.3`
- `cyber_vision = 5.2.0`
- `cyber_vision = 5.2.1`
- `cyber_vision = 5.3.0`
- `cyber_vision = 5.3.1`
- `cyber_vision = 5.3.2`
- `secure_firewall_threat_defense = 7.2.0`
- `secure_firewall_threat_defense = 7.2.0.1`
- `secure_firewall_threat_defense = 7.2.1`
- `secure_firewall_threat_defense = 7.2.2`
- `secure_firewall_threat_defense = 7.2.3`
- `secure_firewall_threat_defense = 7.2.4`
- `secure_firewall_threat_defense = 7.2.4.1`
- `secure_firewall_threat_defense = 7.2.5`
- `secure_firewall_threat_defense = 7.2.5.1`
- `secure_firewall_threat_defense = 7.2.5.2`
- `secure_firewall_threat_defense = 7.2.6`
- `secure_firewall_threat_defense = 7.2.7`
- `secure_firewall_threat_defense = 7.2.8`
- `secure_firewall_threat_defense = 7.2.8.1`
- `secure_firewall_threat_defense = 7.2.9`
- `secure_firewall_threat_defense = 7.2.10`
- `secure_firewall_threat_defense = 7.2.10.2`
- `secure_firewall_threat_defense = 7.3.0`
- `secure_firewall_threat_defense = 7.3.1`
- `secure_firewall_threat_defense = 7.3.1.1`
- `secure_firewall_threat_defense = 7.3.1.2`
- `secure_firewall_threat_defense = 7.4.0`
- `secure_firewall_threat_defense = 7.4.1`
- `secure_firewall_threat_defense = 7.4.1.1`
- `secure_firewall_threat_defense = 7.4.2`
- `secure_firewall_threat_defense = 7.4.2.1`
- `secure_firewall_threat_defense = 7.4.2.2`
- `secure_firewall_threat_defense = 7.4.2.3`
- `secure_firewall_threat_defense = 7.4.2.4`
- `secure_firewall_threat_defense = 7.4.3`
- `secure_firewall_threat_defense = 7.6.0`
- `secure_firewall_threat_defense = 7.6.1`
- `secure_firewall_threat_defense = 7.6.2`
- `secure_firewall_threat_defense = 7.6.2.1`
- `secure_firewall_threat_defense = 7.7.0`
- `secure_firewall_threat_defense = 7.7.10`
- `secure_firewall_threat_defense = 7.7.10.1`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.9.4`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.9.5e`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.1a`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.2`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.3`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.3a`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4a`
- `unified_threat_defense_snort_intrusion_prevention_system_engine = 17.12.4b`

## Remediation

Upgrade past the affected range:

- `snort 3.9.3.0`