Multiple Cisco Products Snort 3 SMTP MIME Denial of Service Vulnerability

Summary

Multiple Cisco products are affected by a vulnerability in the Snort 3 SMTP MIME Decoder that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a lack of error checking when the MIME fields of the SMTP header are parsed. An attacker could exploit this vulnerability by sending crafted SMTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

Timeline

1. Oct 21, 2026, 4:12 PM UTCCVE published
2. Oct 21, 2026, 5:21 PM UTCCISA SSVC assessment

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

3. Oct 22, 2026, 7:05 AM UTCFirst seen by cve.now
4. Oct 22, 2026, 7:11 PM UTCRecord last updated

Affected versions

• Cisco Cisco Open Source Snort3

  3.1.2.0, 3.1.3.0, 3.1.4.0, 3.1.5.0, 3.1.6.0, 3.1.7.0, 3.1.8.0, 3.1.9.0, 3.1.10.0, 3.1.12.0, 3.1.13.0, 3.1.14.0, 3.1.15.0, 3.1.16.0, 3.1.17.0, 3.1.18.0, 3.1.19.0, 3.1.20.0, 3.1.21.0, 3.1.22.0, 3.1.23.0, 3.1.24.0, 3.1.25.0, 3.1.27.0, 3.1.28.0, 3.1.29.0, 3.1.30.0, 3.1.31.0, 3.1.32.0, 3.1.36.0, and 70 more

• Cisco Cisco Secure Firewall Threat Defense (FTD) Software

  7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.2.0, 7.0.2.1, 7.0.3, 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, 7.2.4, 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, 7.0.6.2, 7.4.1.1, 7.2.7, 7.2.5.2, and 29 more

• Cisco Cisco UTD SNORT IPS Engine Software

  3.17.1S, 16.12.3, Fuji-16.9.5, 16.12.4, 17.3.1a, 16.6.6, 16.12.2, Fuji-16.9.6, 3.17.0S, Fuji-16.9.3, Denali-16.3.7, Fuji-16.9.2, Fuji-16.9.4, Everest-16.6.4, Everest-16.6.3, 16.6.5, Denali-16.3.5, 17.2.1r, 17.1.1, Everest-16.6.2, 16.6.7a, Denali-16.3.4, 16.6.1, Denali-16.3.9, Denali-16.3.3, 16.12.1a, 17.3.2, 17.4.1a, 16.12.5, Fuji-16.9.7, and 77 more

References 1