CVE-2026-20218CWE-121

CVE-2026-20218

Medium · published October 21, 2026

CVSS v3.1
5.8
EPSS
0%
Percentile
34.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00416 · 34.8th percentile
Weakness
CWE-121 · Stack-based Buffer Overflow
Published
2026-10-21T21:18Z
References (1)
EPSS history
Timeline
  • 23 OCT 03:56Z
    EPSS moved — → 0%
    epss
  • 21 OCT 16:12Z
    Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
    cvelistv5
  • 21 OCT 16:12Z
    Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
    cvelistv5