CVE-2019-1687

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software TCP Proxy Denial of Service Vulnerability

HIGH

7.5

CVSS Score

Published: May 3, 2019 at 03:00 PM UTC

Updated: August 11, 2026 at 07:33 PM UTC

14 products affected across 1 vendorAdaptive Security ApplianceSecure Firewall Threat DefenseASA 5580

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Severity

HIGH7.5

Exploit prediction

EPSS 3%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Adaptive Security Appliance · Cisco

95%

v < 9.4.4.34v < 9.8.4v < 9.9.2.509.10 ≤ v < 9.10.1.179.5 ≤ v < 9.6.4.259.7 ≤ v < 9.8.49.9 ≤ v < 9.9.2.50

Affected range stops below 9.10.1.17, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.4.4.34, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.6.4.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.8.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.9.2.50, so it looks safe — our inference, not a vendor statement

cisco-asa-5505 (environment) · cisco-asa-5510 (environment) · cisco-asa-5512-x (environment) · cisco-asa-5515-x (environment) · cisco-asa-5520 (environment) · cisco-asa-5525-x (environment) · cisco-asa-5540 (environment) · cisco-asa-5545-x (environment) · cisco-asa-5550 (environment) · cisco-asa-5555-x (environment) · cisco-asa-5580 (environment) · cisco-asa-5585-x (environment)

Secure Firewall Threat Defense · Cisco

95%

6.0.0 ≤ v < 6.2.3.126.3.0 ≤ v < 6.3.0.3

ASA 5505 · Ciscodevice

80%

All versions

ASA 5510 · Ciscodevice

80%

All versions

Asa 5512-X · Ciscodevice

80%

All versions