Cisco Firepower Threat Defense Software NULL Character Obfuscation Detection Bypass Vulnerability

Published 7 y ago 2019-11-05 · modified 2 mo ago 2026-08-11 · JSON

CVSS

5.8

v3.0 · CNA

CISA KEV

not known exploited

EPSS

1.0%

percentile 64%

Public exploits

none known

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.

CISA SSVC assessment

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 23 mo ago 2024-11-19

Exploit prediction (EPSS)

1.04% probability of exploitation in the next 30 days, higher than 64% of all scored CVEs.

CVSS scores

Assigned by	Version	Score	Vector
CNA	3.0	5.8	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`
NVD	3.1	5.8	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`
CNA	3.0	5.8	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`
NVD	2.0	5.0	`AV:N/AC:L/Au:N/C:N/I:P/A:N`

Affected products

Cisco Cisco Firepower Threat Defense Software

Classification

Weakness

CWE-264 Permissions, Privileges, and Access Controls
CWE-20 Improper Input Validation

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-20190816-ftd-null · vendor-advisory, x_refsource_CISCO, x_transferred

Sources

CVE List: CVE-2019-1981
NVD: CVE-2019-1981

vulnwire keeps one entry per vulnerability: the CVE id wins, then GHSA; records that alias each other are merged. Machine-readable: JSON.

Summary