TI-2019-09451 Aliases CVE-2019-12655 GHSA-56j6-c5p2-5rq5

Cisco IOS XE Software FTP Application Layer Gateway for NAT, NAT64, and ZBFW Denial of Service Vulnerability

MEDIUM 43CWE-20Published 2019-09-25 · Updated 2024-11-19

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-120 and the CVSS impact.

Summary

A vulnerability in the FTP application layer gateway (ALG) functionality used by Network Address Translation (NAT), NAT IPv6 to IPv4 (NAT64), and the Zone-Based Policy Firewall (ZBFW) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a buffer overflow that occurs when an affected device inspects certain FTP traffic. An attacker could exploit this vulnerability by performing a specific FTP transfer through the device. A successful exploit could allow the attacker to cause the device to reload.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01973 80th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco IOS XE Software 3.16.8S	all versions	—	No fix listed	CNA

Cisco IOS XE Software 3.16.8S VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPE	Versions	Role	Vendor
cpe:2.3:o:cisco:ios::::::::	3.16.8s to before 16.3.8; 16.10.1 to before 16.11.1	Vulnerable	Cisco
cpe:2.3:o:cisco:ios:16.6.4:::::::*	16.6.4	Vulnerable	Cisco
cpe:2.3:o:cisco:ios:16.6.5:::::::*	16.6.5	Vulnerable	Cisco
cpe:2.3:o:cisco:ios:16.9.1:::::::*	16.9.1	Vulnerable	Cisco
cpe:2.3:o:cisco:ios:16.9.2:::::::*	16.9.2	Vulnerable	Cisco

cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:* Versions 3.16.8s to before 16.3.8; 16.10.1 to before 16.11.1 Vulnerable ·Cisco
cpe:2.3:o:cisco:ios:16.6.4:*:*:*:*:*:*:* Versions 16.6.4 Vulnerable ·Cisco
cpe:2.3:o:cisco:ios:16.6.5:*:*:*:*:*:*:* Versions 16.6.5 Vulnerable ·Cisco
cpe:2.3:o:cisco:ios:16.9.1:*:*:*:*:*:*:* Versions 16.9.1 Vulnerable ·Cisco
cpe:2.3:o:cisco:ios:16.9.2:*:*:*:*:*:*:* Versions 16.9.2 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2019-12655
2026-10-03 Alias added: GHSA-56j6-c5p2-5rq5

References

Advisory 1

20190925 Cisco IOS XE Software FTP Application Layer Gateway for NAT, NAT64, and ZBFW Denial of Service Vulnerability

TI-2018-00138 Improper input validation in Cisco IOS and IOS XE KEVCVSS 3.1CRITICAL 9.8
TI-2017-09019 Improper input validation in Cisco IOS and IOS XE KEVCVSS 3.1CRITICAL 9.8
TI-2017-02977 Improper input validation in Cisco IOS and IOS XE Software KEVCVSS 3.1CRITICAL 9.8
TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
TI-2017-04499 Memory corruption in Cisco IOS KEVCVSS 3.1HIGH 8.8
TI-2017-04498 Memory corruption in Cisco IOS KEVCVSS 3.1HIGH 8.8

See all 617 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences