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Cisco ASA Improper Restriction of Operations within the Bounds of a Memory Buffer (CVE-2021-34783)
high Tenable OT Security Plugin ID 506192
Synopsis
The remote OT asset is affected by a vulnerability.Description
A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.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.See Also
Plugin Details
Severity: High
ID: 506192
File Name: tenable_ot_cisco_CVE-2021-34783.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: 23.18
CVSS v2
Risk Factor: High
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
CVSS Score Source: CVE-2021-34783
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: 10/27/2021
Vulnerability Publication Date: 10/27/2021
Reference Information
CVE: CVE-2021-34783