Cisco ASA Improper Input Validation (CVE-2021-34790)

medium Tenable OT Security Plugin ID 506140

Synopsis

The remote OT asset is affected by a vulnerability.

Description

Multiple vulnerabilities in the Application Level Gateway (ALG) for the Network Address Translation (NAT) feature of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the ALG and open unauthorized connections with a host located behind the ALG. For more information about these vulnerabilities, see the Details section of this advisory. Note: These vulnerabilities have been publicly discussed as NAT Slipstreaming.

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Solution

Refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 506140

File Name: tenable_ot_cisco_CVE-2021-34790.nasl

Version: 1.1

Type: Remote

Family: Tenable.ot

Published: 10/6/2026

Updated: 10/6/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2021-34790

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Vulnerability Information

CPE: cpe:/o:cisco:adaptive_security_appliance_software:9

Required KB Items: Tenable.ot/Cisco

Patch Publication Date: 10/27/2021

Vulnerability Publication Date: 10/27/2021

Reference Information

CVE: CVE-2021-34790

CWE: 20, 358

Detections

Analytics