DoS: SSL handshake triggers Snort 3 Detection Engine restart (Cisco)
CVE-2026-20005 Published on March 4, 2026
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 parsing of the SSL handshake ingress packets. An attacker could exploit this vulnerability by sending crafted SSL handshake packets. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine restarts unexpectedly.
Vulnerability Analysis
CVE-2026-20005 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Type
Missing Report of Error Condition
The software encounters an error but does not provide a status code or return value to indicate that an error has occurred.
Products Associated with CVE-2026-20005
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Affected Versions
Cisco Secure Firewall Threat Defense (FTD) Software:- Version 7.6.0 is affected.
- Version 7.6.1 is affected.
- Version 7.6.2 is affected.
- Version 7.6.2.1 is affected.
- Version 7.7.0 is affected.
- Version 7.7.10 is affected.
- Version 7.7.10.1 is affected.
- Version 3.0.4 is affected.
- Version 3.0.0 is affected.
- Version 3.0.1 is affected.
- Version 3.0.2 is affected.
- Version 3.0.3 is affected.
- Version 3.0.5 is affected.
- Version 3.0.6 is affected.
- Version 3.1.0 is affected.
- Version 3.1.2 is affected.
- Version 3.1.1 is affected.
- Version 3.2.3 is affected.
- Version 3.2.1 is affected.
- Version 3.2.4 is affected.
- Version 3.2.0 is affected.
- Version 3.2.2 is affected.
- Version 4.0.0 is affected.
- Version 4.0.1 is affected.
- Version 4.0.2 is affected.
- Version 4.0.3 is affected.
- Version 4.1.0 is affected.
- Version 4.1.1 is affected.
- Version 4.1.2 is affected.
- Version 4.1.3 is affected.
- Version 4.1.4 is affected.
- Version 4.1.5 is affected.
- Version 4.1.6 is affected.
- Version 4.1.7 is affected.
- Version 4.2.0 is affected.
- Version 4.2.1 is affected.
- Version 4.2.4 is affected.
- Version 4.2.6 is affected.
- Version 4.2.2 is affected.
- Version 4.2.3 is affected.
- Version 4.3.0 is affected.
- Version 4.3.1 is affected.
- Version 4.3.2 is affected.
- Version 4.3.3 is affected.
- Version 4.4.0 is affected.
- Version 4.4.1 is affected.
- Version 4.4.2 is affected.
- Version 4.4.3 is affected.
- Version 5.0.0 is affected.
- Version 5.0.1 is affected.
- Version 5.0.2 is affected.
- Version 5.1.1 is affected.
- Version 5.1.2 is affected.
- Version 5.1.3 is affected.
- Version 5.2.0 is affected.
- Version 5.2.1 is affected.
- Version 5.3.0 is affected.
- Version 5.3.1 is affected.
- Version 5.3.2 is affected.
- Version 17.2.1r is affected.
- Version 17.3.1a is affected.
- Version 17.3.2 is affected.
- Version 17.3.3 is affected.
- Version 17.3.4a is affected.
- Version 17.3.6 is affected.
- Version 17.3.5 is affected.
- Version 17.3.7 is affected.
- Version 17.3.8 is affected.
- Version 17.4.1a is affected.
- Version 17.4.2 is affected.
- Version 17.4.1b is affected.
- Version 17.5.1a is affected.
- Version 17.6.1a is affected.
- Version 17.6.2 is affected.
- Version 17.6.3a is affected.
- Version 17.6.4 is affected.
- Version 17.6.5 is affected.
- Version 17.6.6 is affected.
- Version 17.6.7 is affected.
- Version 17.6.8a is affected.
- Version 17.7.1a is affected.
- Version 17.7.2 is affected.
- Version 17.10.1a is affected.
- Version 17.9.1a is affected.
- Version 17.9.2a is affected.
- Version 17.9.3a is affected.
- Version 17.9.4 is affected.
- Version 17.9.5a is affected.
- Version 17.9.6 is affected.
- Version 17.9.5e is affected.
- Version 17.9.5f is affected.
- Version 17.9.7a is affected.
- Version 17.9.8 is affected.
- Version 17.9.7b is affected.
- Version 17.8.1a is affected.
- Version 17.11.1a is affected.
- Version 17.12.1a is affected.
- Version 17.12.2 is affected.
- Version 17.12.3 is affected.
- Version 17.12.4 is affected.
- Version 17.12.4a is affected.
- Version 17.12.4b is affected.
- Version 17.12.5 is affected.
- Version 17.12.5a is affected.
- Version 17.12.5b is affected.
- Version 17.12.5c is affected.
- Version 17.12.6 is affected.
- Version 17.12.5d is affected.
- Version 17.13.1a is affected.
- Version 17.14.1a is affected.
- Version 17.15.1a is affected.
- Version 17.15.2a is affected.
- Version 17.15.2c is affected.
- Version 17.15.3 is affected.
- Version 17.15.3a is affected.
- Version 17.15.4 is affected.
- Version 17.15.4c is affected.
- Version 17.16.1a is affected.
- Version 17.17.1 is affected.
- Version 17.18.1a is affected.
- Version 17.18.2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.