CVE-2020-3179: Cisco ASA 5505 Firmware
High severity, CVSS 7.5. EPSS: 2% chance of exploitation in the next 30 days.
A vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory handling error when GRE over IPv6 traffic is processed. An attacker could exploit this vulnerability by sending crafted GRE over IPv6 packets with either IPv4 or IPv6 payload through an affected device. A successful exploit could allow the attacker to cause the device to crash, resulting in a DoS condition.
Affected products
- Cisco ASA 5505 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5510 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5512-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5515-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5520 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5525-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5540 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5545-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5550 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5555-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5580 Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco ASA 5585-X Firmware: version 9.9(2) only; version 101.5(1.26) only
- Cisco Secure Firewall Threat Defense: from 6.3.0, before 6.3.0.5 (fixed in 6.3.0.5); from 6.4.0, before 6.4.0.6 (fixed in 6.4.0.6)
Published 2020-05-06. Last modified 2026-08-11.