CVE-2019-1687

Name: CVE-2019-1687
Creator: NVD / NIST
Published: 2019-05-03T15:29:00.837+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.90%

Last modified Jun 17, 2026

CVE-2019-1687 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A vulnerability in the TCP proxy functionality for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error in TCP-based packet inspection, which could cause the TCP packet to have an invalid Layer 2 (L2)-formatted header. EPSS estimates a 2.90% chance of exploitation in the next 30 days.

Description

A vulnerability in the TCP proxy functionality for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error in TCP-based packet inspection, which could cause the TCP packet to have an invalid Layer 2 (L2)-formatted header. An attacker could exploit this vulnerability by sending a crafted TCP packet sequence to the targeted device. A successful exploit could allow the attacker to cause a DoS condition.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.90%

85.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Adaptive Security Appliance Software	< 9.4.4.34
Cisco	Adaptive Security Appliance Software	>= 9.5, < 9.6.4.25
Cisco	Adaptive Security Appliance Software	>= 9.7, < 9.8.4
Cisco	Adaptive Security Appliance Software	>= 9.9, < 9.9.2.50
Cisco	Adaptive Security Appliance Software	>= 9.10, < 9.10.1.17
Cisco	Firepower Threat Defense	>= 6.0.0, < 6.2.3.12
Cisco	Firepower Threat Defense	>= 6.3.0, < 6.3.0.3

References

http://www.securityfocus.com/bid/108176Broken Link, Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-asa-ftdtcp-dosVendor Advisory
http://www.securityfocus.com/bid/108176Broken Link, Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-asa-ftdtcp-dosVendor Advisory

Timeline

Published: May 3, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-1687?

How severe is CVE-2019-1687?

CVE-2019-1687 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.90% probability of exploitation in the next 30 days.

How do I fix CVE-2019-1687?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-1687?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST