---
id: CVE-2026-20052
title: "A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.\r\n…"
summary: "A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.\r\n…"
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-788
vendor: cisco
product: secure_firewall_threat_defense
affected:
  - 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 = 7.6.0
published: '2026-03-04'
updated: '2026-08-20'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20052'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort3ssl-FBEKYXpH
    label: psirt@cisco.com
tags:
  - nvd
epss: 0.00413
epssPercentile: 0.32806
ingestedAt: '2026-08-20T17:59:04.079Z'
---

## Overview

A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.

This vulnerability is due to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

## Affected

- `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 = 7.6.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.