CVE-2026-20027: Cisco Secure Firewall Threat Defense FTD Software

Medium severity, CVSS 5.3. EPSS: 0.6% chance of exploitation in the next 30 days.

Multiple Cisco products are affected by a vulnerability in the processing of DCE/RPC requests that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to leak sensitive information or to restart, resulting in an interruption of packet inspection. This vulnerability is due to an error in buffer handling logic when processing DCE/RPC requests, which can result in a buffer out-of-bounds read. An attacker could exploit this vulnerability by sending a large number of DCE/RPC requests through an established connection that is inspected by Snort 3. A successful exploit could allow the attacker to obtain sensitive information in the Snort 3 data stream.

Affected products

• Cisco Cisco Secure Firewall Threat Defense FTD Software: version 7.0.0 only; version 7.0.0.1 only; version 7.0.1 only; version 7.1.0 only; version 7.0.1.1 only; version 7.1.0.1 only; …
• Cisco Cisco Utd Snort Ips Engine Software: version 3.17.1S only; version 16.12.3 only; version 16.12.4 only; version 17.3.1a only; version 16.6.6 only; version 16.12.2 only; …

Published 2026-01-07. Last modified 2026-06-17.