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Findings

CVE-2026-20006

A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthentic…

Published Mar 4, 2026 · updated Aug 20, 2026 · cisco secure firewall threat defense

A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition. This vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition. Note: TLS 1.3 is not affected by this vulnerability.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 4, 2026 · NIST NVD

    Detected

    A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition. This vulnerability is due to improper implementation of the TLS protocol. An attacker could exploi

  2. Aug 20, 2026 · NIST NVD

    Updated

    A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition. This vulnerability is due to improper implementation of the TLS protocol. An attacker could exploi

Affected

  • cpe cisco/secure firewall threat defense7.2.0
  • cpe cisco/secure firewall threat defense7.2.0.1
  • cpe cisco/secure firewall threat defense7.2.1
  • cpe cisco/secure firewall threat defense7.2.2
  • cpe cisco/secure firewall threat defense7.2.3
  • cpe cisco/secure firewall threat defense7.2.4
  • cpe cisco/secure firewall threat defense7.2.4.1
  • cpe cisco/secure firewall threat defense7.2.5

Sources

  • CVE.orgVulnerability recordCVE-2026-20006

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2026-20006

    A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of ser

    nvd.nist.gov

References

CVE-2026-20006 · ZeroDay Findings