CVE-2026-20011
Multiple Cisco Products Snort 3 SMTP MIME Denial of Service Vulnerability
CVSS Score
5.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-805 |
| Vendor | cisco |
| Product | cisco open source snort3 |
| Ecosystems | |
| Industries | NetworkingTelecommunications |
| Published | Oct 21, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low
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 3.1.38.0 3.1.39.0 3.1.40.0 3.1.41.0 3.1.42.0 3.1.43.0 3.1.45.0 3.1.47.0 3.1.48.0 3.1.50.0 3.1.51.0 3.1.52.0 3.1.53.0 3.1.55.0 3.1.56.0 3.1.57.0 3.1.58.0 3.1.59.0 3.1.60.0 3.1.61.0 3.1.62.0 3.1.63.0 3.1.64.0 3.1.65.0 3.1.66.0 3.1.67.0 3.1.69.0 3.1.70.0 3.1.71.0 3.1.72.0 3.1.73.0 3.1.74.0 3.1.75.0 3.1.76.0 3.1.77.0 3.1.78.0 3.1.81.0 3.1.82.0 3.1.83.0 3.1.84.0 3.2.1.0 3.2.2.0 3.3.0.0 3.3.1.0 3.3.2.0 3.3.3.0 3.3.4.0 3.3.5.0 3.3.7.0 3.5.0.0 3.5.1.0 3.8.1.0 3.6.0.0 3.6.2.0 3.9.3.0 3.7.2.0 3.7.0.0 3.9.6.0 3.10.0.0 3.7.4.0 3.9.0.0 3.5.2.0 3.6.1.0 3.9.2.0 3.6.3.0 3.9.5.0 3.7.1.0 3.9.7.0 3.7.3.0 3.9.1.0
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 7.3.1.2 7.2.8 7.6.0 7.4.2 7.2.8.1 7.0.6.3 7.4.2.1 7.2.9 7.0.7 7.7.0 7.4.2.2 7.2.10 7.6.1 7.4.2.3 7.0.8 7.6.2 7.7.10 7.7.11 7.0.8.1 7.6.2.1 7.7.10.1 7.4.2.4 7.2.10.2 7.4.3 7.6.4 10.0.0 7.4.4 7.0.9 7.2.11
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 16.6.9 17.3.3 17.5.1a 17.3.4a 17.4.2 17.4.1b 17.6.1a 16.6.10 17.7.1a 16.12.6 Fuji-16.9.8 17.6.2 17.8.1a 16.12.7 17.3.5 17.6.3a 17.7.2 17.9.1a 17.6.4 17.10.1a 17.3.6 16.12.8 17.3.7 17.9.2a 17.6.5 17.11.1a 17.9.3a 17.12.1a 17.9.4 17.6.6 17.3.8 17.12.2 17.13.1a 17.9.5a 17.12.3 17.6.7 17.14.1a 17.12.4 17.12.3a 17.15.1a 17.9.6 17.6.8a 17.16.1a 17.9.5e 17.12.4a 17.15.2c 17.9.5f 17.12.4b 17.15.2a 17.12.5 17.17.1 17.12.5a 17.9.7a 17.15.3a 17.15.3 17.12.5b 17.12.5c 17.15.4 17.9.7b 17.18.1 17.18.1a 17.12.6 17.9.8 17.15.4c 17.12.5d 17.18.2 26.1.1 17.15.5 17.15.5a 17.12.7 17.12.7a 17.12.7b 17.9.9 17.12.8 17.15.6 17.18.4 26.1.2