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9.0

Cisco Snort 3 products could crash or be exploited

CVE-2026-20043 · published 20 days ago
Summary

Cisco's Cyber Vision, Open Source Snort3, Secure Firewall Threat Defense (FTD) and UTD Snort IPS Engine software contain coding errors that may cause out-of-bounds writes, which can lead to crashes or allow an attacker to run code. These issues were found internally and have been fixed in a hardening update released in October 2026. Apply the latest software update from Cisco as soon as possible to protect your systems.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
cisco cisco cyber vision 3.0.0
cisco cisco open source snort3 3.12.2.0
cisco cisco secure firewall threat defense (ftd) software 7.0.0
cisco cisco utd snort ips engine software 17.3.1a
Original advisory text
Multiple Cisco Products Snort 3 Software Hardening Release: October 2026
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.
References
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker full control
Severity
9.0 Critical
Exploitation
<1% chance of attack within 30 days
Type
CWE-787Out-of-bounds Write
Timeline
Published21 Oct 2026
Updated8 Nov 2026
First seen21 Oct 2026
Sources
CVE-2026-20043 · NVD
CVE-2026-20043 · MITRE
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