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UK Cyber Defence
VulnerabilityAwaiting Analysis

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…

MEDIUM 5.8EPSS 0.63%

Does this matter?

Lower severity and a low EPSS score (0.63%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1
5.8 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
EPSS
0.63% probability · 50th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-121
Source
psirt@cisco.com
EPSS trend
0%3%5%22 October 2026: 0.42%26 October 2026: 0.63%22 October 202626 October 2026

EPSS moved from 0.4% on 22 October 2026 to 0.6% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.