CVE-2021-34754: Cisco Secure Firewall Management Center

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

Multiple vulnerabilities in the payload inspection for Ethernet Industrial Protocol (ENIP) traffic for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured rules for ENIP traffic. These vulnerabilities are due to incomplete processing during deep packet inspection for ENIP packets. An attacker could exploit these vulnerabilities by sending a crafted ENIP packet to the targeted interface. A successful exploit could allow the attacker to bypass configured access control and intrusion policies that should be activated for the ENIP packet.

Affected products

• Cisco Secure Firewall Management Center: version 2.9.12 only; version 2.9.14.0 only; version 2.9.16 only; version 2.9.17 only; version 2.9.18 only
• Cisco Secure Firewall Threat Defense: from 6.4.0, before 6.4.0.13 (fixed in 6.4.0.13); from 6.6.0, before 6.6.5.1 (fixed in 6.6.5.1); from 6.7.0, before 6.7.0.3 (fixed in 6.7.0.3); from 7.0.0, before 7.0.1 (fixed in 7.0.1)

Published 2021-10-27. Last modified 2026-08-11.