CVE-2018-0231

What it is

A vulnerability in the Transport Layer Security (TLS) library of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of the affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious TLS message to an interface enabled for Secure Layer Socket (SSL) services on an affected device. Messages using SSL Version 3 (SSLv3) or SSL Version 2 (SSLv2) cannot be be used to exploit this vulnerability. An exploit could allow the attacker to cause a buffer underflow, triggering a crash on an affected device. This vulnerability affects Cisco ASA Software and Cisco FTD Software that is running on the following Cisco products: Adaptive Security Virtual Appliance (ASAv), Firepower Threat Defense Virtual (FTDv), Firepower 2100 Series Security Appliance. Cisco Bug IDs: CSCve18902, CSCve34335, CSCve38446.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

4.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2018-04-19 20:29 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-11 19:37 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 4.4% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2018-04-19 20:29 UTC

Last modified

2026-08-11 19:37 UTC

Exploit probability

4.4% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Cisco Adaptive Security Appliance Software 9.8\(1\)
• Cisco Adaptive Security Appliance Software 98.1\(1.154\)
• Cisco Secure Firewall Threat Defense < 6.1.0.6
• Cisco Secure Firewall Threat Defense < 6.2.2.1

Attack profile CVSS 3.0 · 8.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2018-0231.md and follow it. Check whether this project is affected by CVE-2018-0231. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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