Improper Check for Unusual or Exceptional Conditions in Snort - CVE-2026-20197
Published: October 21, 2026
Vulnerability identifier: #VU156720
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-20197
CWE-ID: CWE-754
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by triggering an unexpected restart of the Snort 3 Detection Engine, interrupting packet inspection.
The vulnerability exists due to incomplete error checking in the Snort 3 Teredo Detection Engine when parsing Teredo packets. A remote attacker can send a crafted Teredo packet to a targeted device for Snort 3 to parse to trigger an unexpected engine restart and interrupt packet inspection.
Open Source Snort 3 is affected only when configured to parse Netflow Protocol connections.
Affected software
Snort
How to mitigate CVE-2026-20197
Install security update from vendor's website.
Snort - update to 3.12.4.0