Cisco ASA Stack-based Buffer Overflow (CVE-2021-34704)

high Tenable OT Security Plugin ID 506184

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Refer to the vendor advisory.

Plugin Details

Severity: High

ID: 506184

File Name: tenable_ot_cisco_CVE-2021-34704.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: 3

Percentile: 23.63

CVSS v2

Risk Factor: High

Base Score: 7.1

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

CVSS Score Source: CVE-2021-34704

CVSS v3

Risk Factor: High

Base Score: 7.5

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

Vulnerability Information

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

Required KB Items: Tenable.ot/Cisco

Patch Publication Date: 1/11/2022

Vulnerability Publication Date: 1/11/2022

Reference Information

CVE: CVE-2021-34704

CWE: 121, 787

Detections

Analytics