CVE intelligence

CVE-2026-20218

Vulnerability intelligence

Published Oct 21, 2026Sources checked Oct 21, 2026

5.8MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-20218 and is rated Medium severity with a CVSS score of 5.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Cisco Security Advisories guidance

Vendor revision: Oct 21, 2026

To remediate the vulnerabilities that were disclosed on October 21, 2026, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.

CISA KEVNot listedBased on the latest collected catalog

EPSSUnavailableNo current score collected

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-20218?

A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.

This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine of a targeted device.

A successful exploit could allow the attacker to cause an overflow of stack data, which could result in a DoS condition.

Source: NVD