CVE-2019-1873

Cisco ASA and FTD Software Cryptographic TLS and SSL Driver Denial of Service Vulnerability

HIGH
8.6
CVSS Score
Published: July 10, 2019 at 05:30 PM UTC
Updated: June 17, 2026 at 02:29 AM UTC
11 products affected across 1 vendorASA 5506H X FirmwareASA 5508-x FirmwareASA 5506W X Firmware

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Severity
HIGH8.6
Exploit prediction
EPSS 2%
SSVC
No known exploit

Description

A vulnerability in the cryptographic driver for Cisco Adaptive Security Appliance Software (ASA) and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reboot unexpectedly. The vulnerability is due to incomplete input validation of a Secure Sockets Layer (SSL) or Transport Layer Security (TLS) ingress packet header. An attacker could exploit this vulnerability by sending a crafted TLS/SSL packet to an interface on the targeted device. An exploit could allow the attacker to cause the device to reload, which will result in a denial of service (DoS) condition. Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed and transparent firewall mode and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. A valid SSL or TLS session is required to exploit this vulnerability.

Affected

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

cisco-asa-5506-x (same device)
cisco-asa-5506h-x (same device)
cisco-asa-5506w-x (same device)
cisco-asa-5508-x (same device)
cisco-asa-5516-x (same device)
v < 9.10.1.22v < 9.12.2v < 9.4.4.36v < 9.6.4.29v < 9.8.4.3v < 9.9.2.52
Affected range stops below 9.10.1.22, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.12.2, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.4.4.36, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.6.4.29, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.8.4.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.9.2.52, so it looks safe — our inference, not a vendor statement
All versions
All versions
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400CWE-20

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