CVE-2026-20011
MEDIUMCVSS 5.8/10
Last modified
CVE-2026-20011 is a medium-severity vulnerability rated 5.8/10 on the CVSS scale. 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.
Description
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.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | 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 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-20011?
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.
How severe is CVE-2026-20011?
CVE-2026-20011 has a CVSS score of 5.8/10 (MEDIUM severity).
How do I fix CVE-2026-20011?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-20011?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST