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CVE-2026-20218: Stack-based Buffer Overflow in Cisco Cisco Open Source Snort3

0
Medium
VulnerabilityCVE-2026-20218cvecve-2026-20218
Published: 10/21/2026 (10/21/2026, 16:12:38 UTC)
Source: CVE Database V5
Vendor/Project: Cisco
Product: Cisco Open Source Snort3

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 v3.1

Score 5.8medium

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Affected software

Cisco

Cisco Open Source Snort3

Affected versions
=3.12.2.0=3.1.2.0=3.1.3.0=3.1.4.0=3.1.5.0=3.1.6.0=3.1.7.0=3.1.8.0=3.1.9.0=3.1.10.0=3.1.12.0=3.1.13.0=3.1.14.0=3.1.15.0=3.1.16.0=3.1.17.0=3.1.18.0=3.1.19.0=3.1.20.0=3.1.21.0=3.1.22.0=3.1.23.0=3.1.24.0=3.1.25.0=3.1.27.0=3.1.28.0=3.1.29.0=3.1.30.0=3.1.31.0=3.1.32.0=3.1.36.0=3.1.38.0=3.1.39.0=3.1.40.0=3.1.41.0=3.1.42.0=3.1.43.0=3.1.45.0=3.1.47.0=3.1.48.0=3.1.50.0=3.1.51.0=3.1.52.0=3.1.53.0=3.1.55.0=3.1.56.0=3.1.57.0=3.1.58.0=3.1.59.0=3.1.60.0=3.1.61.0=3.1.62.0=3.1.63.0=3.1.64.0=3.1.65.0=3.1.66.0=3.1.67.0=3.1.69.0=3.1.70.0=3.1.71.0=3.1.72.0=3.1.73.0=3.1.74.0=3.1.75.0=3.1.76.0=3.1.77.0=3.1.78.0=3.1.81.0=3.1.82.0=3.1.83.0=3.1.84.0=3.2.1.0=3.2.2.0=3.3.0.0=3.3.1.0=3.3.2.0=3.3.3.0=3.3.4.0=3.3.5.0=3.3.7.0=3.5.0.0=3.5.1.0=3.8.1.0=3.6.0.0=3.6.2.0=3.9.3.0=3.7.2.0=3.7.0.0=3.9.6.0=3.10.0.0=3.10.2.0=3.7.4.0=3.9.0.0=3.5.2.0=3.12.1.0=3.6.1.0=3.9.2.0=3.6.3.0=3.9.5.0=3.7.1.0=3.9.7.0=3.7.3.0=3.10.1.0=3.9.1.0=3.11.1.0

Cisco

Cisco Secure Firewall Threat Defense (FTD) Software

Affected versions
=7.2.0=7.2.0.1=7.2.1=7.3.0=7.2.2=7.2.3=7.3.1=7.2.4=7.2.5=7.2.4.1=7.3.1.1=7.4.0=7.2.5.1=7.4.1=7.2.6=7.4.1.1=7.2.7=7.2.5.2=7.3.1.2=7.2.8=7.6.0=7.4.2=7.2.8.1=7.4.2.1=7.2.9=7.7.0=7.4.2.2=7.2.10=7.6.1=7.4.2.3=7.6.2=7.7.10=7.7.11=7.6.2.1=7.7.10.1=7.4.2.4=7.2.10.2=7.4.3=7.6.4=10.0.0=7.4.4=7.2.11=7.4.7

Cisco

Cisco UTD SNORT IPS Engine Software

Affected versions
=17.12.1a=17.12.2=17.13.1a=17.12.3=17.14.1a=17.12.4=17.12.3a=17.15.1a=17.16.1a=17.12.4a=17.15.2c=17.12.4b=17.15.2a=17.12.5=17.17.1=17.12.5a=17.15.3a=17.15.3=17.12.5b=17.12.5c=17.15.4=17.18.1=17.18.1a=17.12.6=17.15.4c=17.12.5d=17.18.2=26.1.1=17.15.5=17.15.5a=17.12.7=17.12.7a=17.12.7b=17.18.3a=17.12.8=17.15.6=17.18.4=26.1.2

Technical Details

Data Version
5.2
Assigner Short Name
cisco
Date Reserved
2025-10-08T11:59:15.398Z
Cvss Version
3.1
State
PUBLISHED

Threat ID: 6ad8e8d24d27ba8daac3b6b9

Added to database: 10/21/2026, 16:31:14 UTC

Last updated: 10/22/2026, 00:01:27 UTC

Views: 4

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