Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability

Summary

Multiple Cisco products are affected by a vulnerability in the Snort 3 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 parsing the Multicast DNS fields of the HTTP header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine unexpectedly restarts.

Timeline

1. Mar 4, 2026, 5:49 PM UTCCVE published
2. Mar 4, 2026, 8:45 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Mar 4, 2026, 8:45 PM UTCRecord last updated

Affected versions

• Cisco Cisco Cyber Vision

  3.0.0, 3.0.2, 3.0.3, 3.0.1, 3.1.0, 3.0.4, 3.1.1, 3.1.2, 3.2.0, 3.0.5, 3.2.1, 3.0.6, 3.2.2, 3.2.3, 3.2.4, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.2.0, 4.2.1, 4.1.5, 4.2.2, 4.2.X, 4.2.3, and 24 more

• Cisco Cisco Secure Firewall Threat Defense (FTD) Software

  7.0.0, 7.0.0.1, 7.0.1, 7.1.0, 7.0.1.1, 7.1.0.1, 7.0.2, 7.2.0, 7.0.2.1, 7.0.3, 7.1.0.2, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5, 7.3.0, 7.2.2, 7.2.3, 7.3.1, 7.1.0.3, 7.2.4, 7.0.6, 7.2.5, 7.2.4.1, 7.3.1.1, 7.4.0, 7.0.6.1, 7.2.5.1, 7.4.1, 7.2.6, and 27 more

• Cisco Cisco UTD SNORT IPS Engine Software

  17.3.1a, 17.2.1r, 17.3.2, 17.4.1a, 17.5.1, 17.3.3, 17.5.1a, 17.3.4, 17.3.4a, 17.4.2, 17.4.1b, 17.6.1a, 17.7.1a, 17.6.2, 17.8.1a, 17.3.5, 17.6.3, 17.6.3a, 17.7.2, 17.9.1a, 17.6.4, 17.10.1a, 17.3.6, 17.3.7, 17.9.2a, 17.6.5, 17.11.1a, 17.9.3a, 17.12.1a, 17.9.4, and 41 more

References 1