Live › vulnerability › CVE-2026-20197
Go to dashboardSnort 3, the intrusion detection engine shipped in several Cisco products, mishandles certain Teredo tunnel packets because error checking is incomplete. A remote attacker without credentials can send one crafted packet to make the Snort 3 detection engine restart, interrupting packet inspection.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Organizations running Cisco products that include the Snort 3 detection engine with Teredo detection active, where inspection traffic reaches the device from untrusted networks. Teams not running Cisco products with Snort 3 can skip it.
No product ranges from the sources yet.
Unknown from the sources.
Unknown from the sources.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.
This vulnerability is due to incomplete error checking when Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.
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