What’s Vulnerable › Vulnerabilities
CVE-2021-34753: Cisco Firepower Threat Defense Ethernet Industrial Protocol Policy Bypass Vulnerabilities
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2024-11-15 · updated 2026-08-11
- Weakness: CWE-284
Description
A vulnerability 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. This vulnerability is due to incomplete processing during deep packet inspection for ENIP packets. An attacker could exploit this vulnerability 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 trigger and drop for the ENIP packet.
Affected products
- Cisco Firepower Threat Defense Software: before 6.4.0.13; from 6.5.0 before 6.6.5.1; from 6.7.0 before 6.7.0.3; 7.0.0 — fixed in 6.4.0.13, 6.6.5.1, 6.7.0.3
How to fix
Upgrade to a fixed version: Cisco Firepower Threat Defense Software 6.4.0.13, 6.6.5.1, 6.7.0.3. Check the vendor advisory for mitigations.
References
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