---
id: CVE-2019-1981
title: >-
  A vulnerability in the normalization functionality of Cisco Firepower Threat
  Defense Software, Cisco FirePOWER Services Software for ASA, and Cisco
  Firepower Management Center Software could allow an unauthenticated, remote
  attacker to b…
summary: >-
  A vulnerability in the normalization functionality of Cisco Firepower Threat
  Defense Software, Cisco FirePOWER Services Software for ASA, and Cisco
  Firepower Management Center Software could allow an unauthenticated, remote
  attacker to b…
severity: medium
cvss: 5.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'
cwe:
  - CWE-264
  - CWE-20
vendor: cisco
product: firepower_services_software_for_asa
affected:
  - firepower_services_software_for_asa
  - 'secure_firewall_management_center >= 2.9.12, <= 2.9.12.15'
  - 'secure_firewall_management_center >= 2.9.13, <= 2.9.13.6'
  - 'secure_firewall_management_center >= 2.9.14.0, <= 2.9.14.5'
  - secure_firewall_management_center = 2.9.15
  - secure_firewall_management_center = 2.9.16
  - secure_firewall_threat_defense
published: '2019-11-05'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-1981'
references:
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190816-ftd-null
    label: psirt@cisco.com
  - url: >-
      https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190816-ftd-null
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01042
epssPercentile: 0.62031
ingestedAt: '2026-08-11T19:48:27.242Z'
---

## Overview

A vulnerability in the normalization functionality of Cisco Firepower Threat Defense Software, Cisco FirePOWER Services Software for ASA, and Cisco Firepower Management Center Software could allow an unauthenticated, remote attacker to bypass filtering protections. The vulnerability is due to insufficient normalization of a text-based payload. An attacker could exploit this vulnerability by sending traffic that contains specifically obfuscated payloads through an affected device. An exploit could allow the attacker to bypass filtering and deliver malicious payloads to protected systems that would otherwise be blocked.

## Affected

- `firepower_services_software_for_asa`
- `secure_firewall_management_center >= 2.9.12, <= 2.9.12.15`
- `secure_firewall_management_center >= 2.9.13, <= 2.9.13.6`
- `secure_firewall_management_center >= 2.9.14.0, <= 2.9.14.5`
- `secure_firewall_management_center = 2.9.15`
- `secure_firewall_management_center = 2.9.16`
- `secure_firewall_threat_defense`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.