CVE-2026-20043

Critical

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20043 are related to issues concerning out-of-bounds writes that are grouped under the Common Weakness Enumeration (CWE) Base CWE-787.

SeverityCritical
CVSS9.0
Exploit probability—
ProductCisco Cyber Vision
PublishedOct 21, 2026
First seenOct 21, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco Cyber Vision3.0.0, 3.0.2, 3.0.3, 3.0.1, 3.1.0, 3.0.4, 3.1.1, 3.1.2, 3.2.0, 3.0.5, 3.2.1, 3.0.6, 3.2.2, 3.2.3, 3.2.4, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.2.0, 4.2.1, 4.1.5, 4.2.2, 4.2.X, 4.2.3, 4.2.4, 4.2.6, 4.1.6, 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.1.7, 5.0.0, 5.0.1, 5.0.2, 5.1.0, 5.1.1, 5.1.2, 5.1.3, 5.2.0, 5.2.1, 5.3.0, 5.3.1, 5.3.2, 5.3.3, 5.5.1, 5.6.1, 5.4.0, 5.4.1, 5.4.2, 5.7.0, 5.8.1, 5.7.1, 5.8.0, 5.5.2—
Cisco Cisco Open Source Snort33.12.2.0, 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) Software7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.0.2.1, 7.0.3, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5, 7.3.0, 7.2.2, 7.2.3, 7.3.1, 7.2.4, 7.0.6, 7.2.5, 7.2.4.1, 7.3.1.1, 7.4.0, 7.0.6.1, 7.2.5.1, 7.4.1, 7.2.6, 7.0.6.2, 7.4.1.1, 7.2.7, 7.2.5.2, 7.3.1.2—

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