CVE-2026-20043
Awaiting Analysis Awaiting Analysis - Queue

Out-of-Bounds Write in Cisco Snort 3

Publication date: 2026-10-21

Last updated on: 2026-11-07

Assigner: Cisco Systems, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-21
Last Modified
2026-11-07
Generated
2026-11-10
AI Q&A
2026-10-22
EPSS Evaluated
2026-11-09
NVD
CVE-2026-20043
EUVD
EUVD-2026-107372

Affected Vendors & Products

Showing 312 associated CPEs
Vendor Product Version / Range
Cisco Cisco Cyber Vision 3.0.0
Cisco Cisco Cyber Vision 3.0.2
Cisco Cisco Cyber Vision 3.0.3
Cisco Cisco Cyber Vision 3.0.1
Cisco Cisco Cyber Vision 3.1.0
Cisco Cisco Cyber Vision 3.0.4
Cisco Cisco Cyber Vision 3.1.1
Cisco Cisco Cyber Vision 3.1.2
Cisco Cisco Cyber Vision 3.2.0
Cisco Cisco Cyber Vision 3.0.5
Cisco Cisco Cyber Vision 3.2.1
Cisco Cisco Cyber Vision 3.0.6
Cisco Cisco Cyber Vision 3.2.2
Cisco Cisco Cyber Vision 3.2.3
Cisco Cisco Cyber Vision 3.2.4
Cisco Cisco Cyber Vision 4.0.0
Cisco Cisco Cyber Vision 4.0.1
Cisco Cisco Cyber Vision 4.0.2
Cisco Cisco Cyber Vision 4.0.3
Cisco Cisco Cyber Vision 4.1.0
Cisco Cisco Cyber Vision 4.1.1
Cisco Cisco Cyber Vision 4.1.2
Cisco Cisco Cyber Vision 4.1.3
Cisco Cisco Cyber Vision 4.1.4
Cisco Cisco Cyber Vision 4.2.0
Cisco Cisco Cyber Vision 4.2.1
Cisco Cisco Cyber Vision 4.1.5
Cisco Cisco Cyber Vision 4.2.2
Cisco Cisco Cyber Vision 4.2.X
Cisco Cisco Cyber Vision 4.2.3
Cisco Cisco Cyber Vision 4.2.4
Cisco Cisco Cyber Vision 4.2.6
Cisco Cisco Cyber Vision 4.1.6
Cisco Cisco Cyber Vision 4.3.0
Cisco Cisco Cyber Vision 4.3.1
Cisco Cisco Cyber Vision 4.3.2
Cisco Cisco Cyber Vision 4.3.3
Cisco Cisco Cyber Vision 4.4.0
Cisco Cisco Cyber Vision 4.4.1
Cisco Cisco Cyber Vision 4.4.2
Cisco Cisco Cyber Vision 4.4.3
Cisco Cisco Cyber Vision 4.1.7
Cisco Cisco Cyber Vision 5.0.0
Cisco Cisco Cyber Vision 5.0.1
Cisco Cisco Cyber Vision 5.0.2
Cisco Cisco Cyber Vision 5.1.0
Cisco Cisco Cyber Vision 5.1.1
Cisco Cisco Cyber Vision 5.1.2
Cisco Cisco Cyber Vision 5.1.3
Cisco Cisco Cyber Vision 5.2.0
Cisco Cisco Cyber Vision 5.2.1
Cisco Cisco Cyber Vision 5.3.0
Cisco Cisco Cyber Vision 5.3.1
Cisco Cisco Cyber Vision 5.3.2
Cisco Cisco Cyber Vision 5.3.3
Cisco Cisco Cyber Vision 5.5.1
Cisco Cisco Cyber Vision 5.6.1
Cisco Cisco Cyber Vision 5.4.0
Cisco Cisco Cyber Vision 5.4.1
Cisco Cisco Cyber Vision 5.4.2
Cisco Cisco Cyber Vision 5.7.0
Cisco Cisco Cyber Vision 5.8.1
Cisco Cisco Cyber Vision 5.7.1
Cisco Cisco Cyber Vision 5.8.0
Cisco Cisco Cyber Vision 5.5.2
Cisco Cisco Open Source Snort3 3.12.2.0
Cisco Cisco Open Source Snort3 3.1.2.0
Cisco Cisco Open Source Snort3 3.1.3.0
Cisco Cisco Open Source Snort3 3.1.4.0
Cisco Cisco Open Source Snort3 3.1.5.0
Cisco Cisco Open Source Snort3 3.1.6.0
Cisco Cisco Open Source Snort3 3.1.7.0
Cisco Cisco Open Source Snort3 3.1.8.0
Cisco Cisco Open Source Snort3 3.1.9.0
Cisco Cisco Open Source Snort3 3.1.10.0
Cisco Cisco Open Source Snort3 3.1.12.0
Cisco Cisco Open Source Snort3 3.1.13.0
Cisco Cisco Open Source Snort3 3.1.14.0
Cisco Cisco Open Source Snort3 3.1.15.0
Cisco Cisco Open Source Snort3 3.1.16.0
Cisco Cisco Open Source Snort3 3.1.17.0
Cisco Cisco Open Source Snort3 3.1.18.0
Cisco Cisco Open Source Snort3 3.1.19.0
Cisco Cisco Open Source Snort3 3.1.20.0
Cisco Cisco Open Source Snort3 3.1.21.0
Cisco Cisco Open Source Snort3 3.1.22.0
Cisco Cisco Open Source Snort3 3.1.23.0
Cisco Cisco Open Source Snort3 3.1.24.0
Cisco Cisco Open Source Snort3 3.1.25.0
Cisco Cisco Open Source Snort3 3.1.27.0
Cisco Cisco Open Source Snort3 3.1.28.0
Cisco Cisco Open Source Snort3 3.1.29.0
Cisco Cisco Open Source Snort3 3.1.30.0
Cisco Cisco Open Source Snort3 3.1.31.0
Cisco Cisco Open Source Snort3 3.1.32.0
Cisco Cisco Open Source Snort3 3.1.36.0
Cisco Cisco Open Source Snort3 3.1.38.0
Cisco Cisco Open Source Snort3 3.1.39.0
Cisco Cisco Open Source Snort3 3.1.40.0
Cisco Cisco Open Source Snort3 3.1.41.0
Cisco Cisco Open Source Snort3 3.1.42.0
Cisco Cisco Open Source Snort3 3.1.43.0
Cisco Cisco Open Source Snort3 3.1.45.0
Cisco Cisco Open Source Snort3 3.1.47.0
Cisco Cisco Open Source Snort3 3.1.48.0
Cisco Cisco Open Source Snort3 3.1.50.0
Cisco Cisco Open Source Snort3 3.1.51.0
Cisco Cisco Open Source Snort3 3.1.52.0
Cisco Cisco Open Source Snort3 3.1.53.0
Cisco Cisco Open Source Snort3 3.1.55.0
Cisco Cisco Open Source Snort3 3.1.56.0
Cisco Cisco Open Source Snort3 3.1.57.0
Cisco Cisco Open Source Snort3 3.1.58.0
Cisco Cisco Open Source Snort3 3.1.59.0
Cisco Cisco Open Source Snort3 3.1.60.0
Cisco Cisco Open Source Snort3 3.1.61.0
Cisco Cisco Open Source Snort3 3.1.62.0
Cisco Cisco Open Source Snort3 3.1.63.0
Cisco Cisco Open Source Snort3 3.1.64.0
Cisco Cisco Open Source Snort3 3.1.65.0
Cisco Cisco Open Source Snort3 3.1.66.0
Cisco Cisco Open Source Snort3 3.1.67.0
Cisco Cisco Open Source Snort3 3.1.69.0
Cisco Cisco Open Source Snort3 3.1.70.0
Cisco Cisco Open Source Snort3 3.1.71.0
Cisco Cisco Open Source Snort3 3.1.72.0
Cisco Cisco Open Source Snort3 3.1.73.0
Cisco Cisco Open Source Snort3 3.1.74.0
Cisco Cisco Open Source Snort3 3.1.75.0
Cisco Cisco Open Source Snort3 3.1.76.0
Cisco Cisco Open Source Snort3 3.1.77.0
Cisco Cisco Open Source Snort3 3.1.78.0
Cisco Cisco Open Source Snort3 3.1.81.0
Cisco Cisco Open Source Snort3 3.1.82.0
Cisco Cisco Open Source Snort3 3.1.83.0
Cisco Cisco Open Source Snort3 3.1.84.0
Cisco Cisco Open Source Snort3 3.2.1.0
Cisco Cisco Open Source Snort3 3.2.2.0
Cisco Cisco Open Source Snort3 3.3.0.0
Cisco Cisco Open Source Snort3 3.3.1.0
Cisco Cisco Open Source Snort3 3.3.2.0
Cisco Cisco Open Source Snort3 3.3.3.0
Cisco Cisco Open Source Snort3 3.3.4.0
Cisco Cisco Open Source Snort3 3.3.5.0
Cisco Cisco Open Source Snort3 3.3.7.0
Cisco Cisco Open Source Snort3 3.5.0.0
Cisco Cisco Open Source Snort3 3.5.1.0
Cisco Cisco Open Source Snort3 3.8.1.0
Cisco Cisco Open Source Snort3 3.6.0.0
Cisco Cisco Open Source Snort3 3.6.2.0
Cisco Cisco Open Source Snort3 3.9.3.0
Cisco Cisco Open Source Snort3 3.7.2.0
Cisco Cisco Open Source Snort3 3.7.0.0
Cisco Cisco Open Source Snort3 3.9.6.0
Cisco Cisco Open Source Snort3 3.10.0.0
Cisco Cisco Open Source Snort3 3.10.2.0
Cisco Cisco Open Source Snort3 3.7.4.0
Cisco Cisco Open Source Snort3 3.9.0.0
Cisco Cisco Open Source Snort3 3.5.2.0
Cisco Cisco Open Source Snort3 3.12.1.0
Cisco Cisco Open Source Snort3 3.6.1.0
Cisco Cisco Open Source Snort3 3.9.2.0
Cisco Cisco Open Source Snort3 3.6.3.0
Cisco Cisco Open Source Snort3 3.9.5.0
Cisco Cisco Open Source Snort3 3.7.1.0
Cisco Cisco Open Source Snort3 3.9.7.0
Cisco Cisco Open Source Snort3 3.7.3.0
Cisco Cisco Open Source Snort3 3.10.1.0
Cisco Cisco Open Source Snort3 3.9.1.0
Cisco Cisco Open Source Snort3 3.11.1.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.3
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.0.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.4
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.5
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.3.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.3
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.4
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.4.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.6
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.7
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.8
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.6.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.8.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.3
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.9
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.7
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.7.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.10
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.6.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.3
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.6.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.7.10
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.7.11
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.6.2.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.7.10.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.4
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.10.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.3
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.6.4
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 10.0.0
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.4
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.0.9
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.11
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.4.7
Cisco Cisco UTD SNORT IPS Engine Software 17.3.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.3.2
Cisco Cisco UTD SNORT IPS Engine Software 17.4.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.5.1
Cisco Cisco UTD SNORT IPS Engine Software 17.3.3
Cisco Cisco UTD SNORT IPS Engine Software 17.5.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.3.4
Cisco Cisco UTD SNORT IPS Engine Software 17.3.4a
Cisco Cisco UTD SNORT IPS Engine Software 17.4.2
Cisco Cisco UTD SNORT IPS Engine Software 17.4.1b
Cisco Cisco UTD SNORT IPS Engine Software 17.6.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.7.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.6.2
Cisco Cisco UTD SNORT IPS Engine Software 17.8.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.3.5
Cisco Cisco UTD SNORT IPS Engine Software 17.6.3
Cisco Cisco UTD SNORT IPS Engine Software 17.6.3a
Cisco Cisco UTD SNORT IPS Engine Software 17.7.2
Cisco Cisco UTD SNORT IPS Engine Software 17.9.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.6.4
Cisco Cisco UTD SNORT IPS Engine Software 17.10.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.3.6
Cisco Cisco UTD SNORT IPS Engine Software 17.3.7
Cisco Cisco UTD SNORT IPS Engine Software 17.9.2a
Cisco Cisco UTD SNORT IPS Engine Software 17.6.5
Cisco Cisco UTD SNORT IPS Engine Software 17.11.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.3a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.4
Cisco Cisco UTD SNORT IPS Engine Software 17.6.6
Cisco Cisco UTD SNORT IPS Engine Software 17.3.8
Cisco Cisco UTD SNORT IPS Engine Software 17.3.8a
Cisco Cisco UTD SNORT IPS Engine Software 17.6.6a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.4a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.2
Cisco Cisco UTD SNORT IPS Engine Software 17.13.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.5a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.3
Cisco Cisco UTD SNORT IPS Engine Software 17.6.7
Cisco Cisco UTD SNORT IPS Engine Software 17.14.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.4
Cisco Cisco UTD SNORT IPS Engine Software 17.12.3a
Cisco Cisco UTD SNORT IPS Engine Software 17.15.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.6.8
Cisco Cisco UTD SNORT IPS Engine Software 17.9.6
Cisco Cisco UTD SNORT IPS Engine Software 17.6.8a
Cisco Cisco UTD SNORT IPS Engine Software 17.16.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.5e
Cisco Cisco UTD SNORT IPS Engine Software 17.12.4a
Cisco Cisco UTD SNORT IPS Engine Software 17.15.2c
Cisco Cisco UTD SNORT IPS Engine Software 17.9.5f
Cisco Cisco UTD SNORT IPS Engine Software 17.12.4b
Cisco Cisco UTD SNORT IPS Engine Software 17.15.2a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.5
Cisco Cisco UTD SNORT IPS Engine Software 17.17.1
Cisco Cisco UTD SNORT IPS Engine Software 17.12.5a
Cisco Cisco UTD SNORT IPS Engine Software 17.9.7a
Cisco Cisco UTD SNORT IPS Engine Software 17.15.3a
Cisco Cisco UTD SNORT IPS Engine Software 17.15.3
Cisco Cisco UTD SNORT IPS Engine Software 17.12.5b
Cisco Cisco UTD SNORT IPS Engine Software 17.12.5c
Cisco Cisco UTD SNORT IPS Engine Software 17.15.4
Cisco Cisco UTD SNORT IPS Engine Software 17.9.7b
Cisco Cisco UTD SNORT IPS Engine Software 17.18.1
Cisco Cisco UTD SNORT IPS Engine Software 17.18.1a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.6
Cisco Cisco UTD SNORT IPS Engine Software 17.9.8
Cisco Cisco UTD SNORT IPS Engine Software 17.15.4c
Cisco Cisco UTD SNORT IPS Engine Software 17.12.5d
Cisco Cisco UTD SNORT IPS Engine Software 17.18.2
Cisco Cisco UTD SNORT IPS Engine Software 26.1.1
Cisco Cisco UTD SNORT IPS Engine Software 17.15.5
Cisco Cisco UTD SNORT IPS Engine Software 17.15.5a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.7
Cisco Cisco UTD SNORT IPS Engine Software 17.12.7a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.7b
Cisco Cisco UTD SNORT IPS Engine Software 17.9.9
Cisco Cisco UTD SNORT IPS Engine Software 17.18.3a
Cisco Cisco UTD SNORT IPS Engine Software 17.12.8
Cisco Cisco UTD SNORT IPS Engine Software 17.15.6
Cisco Cisco UTD SNORT IPS Engine Software 17.18.4
Cisco Cisco UTD SNORT IPS Engine Software 26.1.2
Cisco Cisco UTD SNORT IPS Engine Software 17.9.10

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

CVE-2026-20043 is an out-of-bounds write vulnerability in Cisco's Open Source Snort 3 software. Out-of-bounds writes occur when a program writes data outside the intended memory buffer, potentially causing crashes, data corruption, or arbitrary code execution.

Impact Analysis

This vulnerability could allow attackers to execute arbitrary code, crash systems, or gain unauthorized access to affected devices running vulnerable versions of Snort 3 or related Cisco products like Cyber Vision, Secure Firewall, or UTD SNORT IPS Engine.

Mitigation Strategies

Apply the latest security updates or patches provided by Cisco for affected products like Snort3, Secure Firewall Threat Defense, or UTD SNORT IPS Engine. Monitor Cisco's security advisories for updates and disable vulnerable features if patches are not immediately available.

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