The vulnerability of the Cisco Secure Firewall Threat Defense (FTD) software-based TLS protocol implementation allows a attacker to cause a service failure.
🗓️ 23 Sep 2026 00:00:00Reported by FSTEC of Russia — Information Security Threat DatabaseType 
bdu_fstec🔗 bdu.fstec.ru👁 3 Views
| Reporter | Title | Published | Views | Family All 8 |
|---|---|---|---|---|
 | Cisco Secure Firewall Threat Defense Software TLS 1.3 Denial of Service Vulnerability | 16 Sep 202616:00 | – | cisco |
 | Cisco Secure Firewall Threat Defense Software TLS 1.3 DoS (cisco-sa-ftd-tls1-3-dos-dLxwFWgF) | 18 Sep 202600:00 | – | nessus |
 | CVE-2026-20135 | 16 Sep 202620:12 | – | cve |
 | CVE-2026-20135 Cisco Secure Firewall Threat Defense Software TLS 1.3 Denial of Service Vulnerability | 16 Sep 202620:12 | – | cvelist |
 | EUVD-2026-81123 | 16 Sep 202620:12 | – | euvd |
 | CVE-2026-20135 | 16 Sep 202621:17 | – | nvd |
 | CVE-2026-20135: Double Free | 16 Sep 202600:00 | – | rapid7 |
 | CVE-2026-20135 Cisco Secure Firewall Threat Defense Software TLS 1.3 Denial of Service Vulnerability | 16 Sep 202620:12 | – | vulnrichment |
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23 Sep 2026 00:00Current
6.5Medium risk
Vulners AI Score6.5
CVSS 27.8
CVSS 38.6
EPSS0.00457