CVE-2019-1981

Cisco Firepower Threat Defense Software NULL Character Obfuscation Detection Bypass Vulnerability

MEDIUM

5.8

CVSS Score

Published: November 5, 2019 at 07:35 PM UTC

Updated: August 11, 2026 at 07:37 PM UTC

3 products affected across 1 vendorSecure Firewall Threat DefenseSecure Firewall Management CenterFirepower Services Software for ASA

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Severity

MEDIUM5.8

Exploit prediction

EPSS 1%

SSVC

No known exploit

Description

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.