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Advisory severityMedium5.8Cisco Updated

Medium [CVE-2026-20019 +3] Multiple Cisco Products Snort 3 Denial of Service Vulnerabilities

This medium-severity Cisco advisory covers CVE-2026-20019 and CVE-2026-20179 and 2 more CVEs affecting Secure Firewall Threat Defense (FTD) Software, Firepower 2100 Series, Firepower 1000 Series.

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.

cisco-sa-snort3-misc-dos-6mB22qAK Source published Source updated

VulniPulse record published Record updated

CVE-2026-20019CVE-2026-20179CVE-2026-20197CVE-2026-76489
Affected products & platforms
CiscoFirewallASA / FirepowerASA 5500
Open source advisory

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Summary

Multiple Cisco products are affected by vulnerabilities in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.

For more information about these vulnerabilities, see the Details section of this advisory.

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.

In addition, for further documentation of improvements and fixes in Open Source Snort 3, see Multiple Cisco Products Snort 3 Security Hardening Release: October 2026.

Affected products named by the advisory: Secure Firewall Threat Defense (FTD) Software; Firepower 2100 Series; Firepower 1000 Series; ASA 5500-X Series Firewalls; and 4 more.

Affected versions
  • Scope: For information about which products were affected by these vulnerabilities at the time of publication, see the following sections. Open Source Snort 3
  • Release 3.x (first fixed: 3.12.4.0)
  • 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 16 hours ago·verify at source

Fixed versions
  • 3.12.4.0
  • 17.12.8
  • 17.15.6
  • 17.18.5
  • 26.1.2
  • 26.2.1

Official advisory · high-confidence parse· fetched 16 hours ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • 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.
  • Release 17.12: upgrade to 17.12.8.
  • Release 17.15: upgrade to 17.15.6.
  • Release 17.18: upgrade to 17.18.5.
  • Release 26.1: upgrade to 26.1.2.
  • Release 26.2: upgrade to 26.2.1.
Workaround status
  • There are no workarounds that address these vulnerabilities.

Official advisory · high-confidence parse· fetched 16 hours ago·verify at source

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