Critical [CVE-2026-20043 +3] Multiple Cisco Products Snort 3 Security Hardening Release: October 2026
This critical-severity Cisco advisory covers CVE-2026-20043 and CVE-2026-20236 and 2 more CVEs affecting Secure Firewall Threat Defense (FTD) Software, Cyber Vision, UTD SNORT IPS Engine Software.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations. This bulletin covers 4 CVEs; its score, affected versions and guidance may apply to different issues within that bulletin.
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Summary
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.
These vulnerabilities were found during internal testing and are not known to be actively exploited.
To assist customers in patching and to streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class - Common Weakness Enumeration (CWE) - and assigned a single Common Vulnerabilities and Exposures Identifier (CVE ID) to each CWE grouping.
Note: Cisco may publish separate security advisories that provide additional details about individual vulnerabilities that are addressed in this release.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of October 21, 2026, Security Advisories.
- Scope: These vulnerabilities affect the following products, regardless of device configuration:
- Release 3.x (first fixed: 3.12.4.0)
- Earlier than 5.6 — Migrate to a fixed release
- Release 5.6 (first fixed: 5.6.0)
- Release 7.0 and earlier (first fixed: 7.0.10)
- Release 7.2 (first fixed: 7.2.12)
- Release 7.4 (first fixed: 7.4.8)
- Release 7.6 (first fixed: 7.6.6)
- Release 7.7 (first fixed: 7.7.13)
- Release 10.0 (first fixed: 10.0.2)
- Release 10.1 (first fixed: 10.1.0)
- Release 17.12 (first fixed: 17.12.8)
- Release 17.15 (first fixed: 17.15.6)
- Release 17.18 (first fixed: 17.18.5)
- Release 26.1 (first fixed: 26.1.2)
- Release 26.2 (first fixed: 26.2.1)
Official advisory · high-confidence parse· fetched 14 hours ago·verify at source
- 3.12.4.0
- 5.6.0
- 7.0.10
- 7.2.12
- 7.4.8
- 7.6.6
- 7.7.13
- 10.0.2
- 10.1.0
- 17.12.8
- 17.15.6
- 17.18.5
- 26.1.2
- 26.2.1
Official advisory · high-confidence parse· fetched 14 hours ago·verify at source
Mitigation checklist
- Upgrade to the first fixed release for your train per the Fixed Releases table in this advisory.
- Release 3.x: upgrade to 3.12.4.0.
- Earlier than 5.6: migrate to a fixed release.
- Release 5.6: upgrade to 5.6.0.
- Release 7.0 and earlier: upgrade to 7.0.10.
- Release 7.2: upgrade to 7.2.12.
- Release 7.4: upgrade to 7.4.8.
- Release 7.6: upgrade to 7.6.6.
- Release 7.7: upgrade to 7.7.13.
- There are no workarounds that address these vulnerabilities.
Official advisory · high-confidence parse· fetched 14 hours ago·verify at source
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