Skip to content
ThreatCluster

Multiple Cisco Products Vulnerable to Snort 3 Denial of Service Flaws

First seen 21 Oct 2026, 16:08 UTC • •
API

Article Content

Browse articles
ThreatCluster AI
ThreatCluster •October 21, 2026 at 17:09 UTC
  • •Cisco products are vulnerable to multiple DoS vulnerabilities in the Snort 3 Detection Engine.
  • •Attackers can exploit these vulnerabilities remotely without authentication.
  • •Cisco has released patches, but no workarounds are available for some vulnerabilities.

Multiple Cisco products are affected by several vulnerabilities in the Snort 3 Detection Engine, allowing unauthenticated remote attackers to trigger unexpected restarts, leading to denial of service (DoS) conditions. The vulnerabilities stem from issues in handling Netflow Protocol connections, GRE traffic, Visual Basic for Applications (VBA) data, and SMTP MIME headers. Cisco has released software updates to address these vulnerabilities, but no workarounds are available for some issues. The vulnerabilities affect Open Source Snort 3 and Cisco Secure Firewall Threat Defense Software, particularly if configured to parse specific protocols. The advisories were published on October 21, 2026, as part of a broader security notification from Cisco.

Start a free Starter trial for enhanced analysis

Ask AI about this cluster

Updated just now How this analysis works

Timeline

2026-10-21
Cisco publishes security advisories
Cisco released multiple advisories detailing vulnerabilities in Snort 3 affecting various products, urging users to apply patches.
Sec.Cloudapps.Cisco
2026-10-21
Patch released for Snort 3 vulnerabilities
Cisco released software updates to address multiple vulnerabilities in the Snort 3 Detection Engine, affecting various Cisco products.
Sec.Cloudapps.Cisco

More articles in this cluster (6)

Following this threat?

Track Cisco and CVE-2026-20019 in your own feed — you're alerted when they show up in new reporting, leak sites or exploitation.

Free account · no card needed

Extracted Entities (11)

1 / 2

Common questions

Which Cisco products are affected?
Open Source Snort 3 and Cisco Secure Firewall Threat Defense Software are among the affected products.
What is the nature of the vulnerabilities?
The vulnerabilities allow unauthenticated remote attackers to trigger unexpected restarts of the Snort 3 Detection Engine, leading to denial of service.
What should organizations do now?
Organizations should apply the latest software updates released by Cisco to mitigate these vulnerabilities.