Cisco Adaptive Security Appliance (ASA) Software TCP Flood DoS (cisco-sa-asa-dos-FCvLD6vR)

high Nessus Plugin ID 311447

Synopsis

The remote device is missing a vendor-supplied security patch.

Description

According to its self-reported version, Cisco ASA Software is affected by a vulnerability.

- A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause incoming TCP SYN packets to be dropped incorrectly. This vulnerability is due to improper handling of new, incoming TCP connections that are destined to management or data interfaces when the device is under a TCP SYN flood attack. An attacker could exploit this vulnerability by sending a crafted stream of traffic to an affected device. A successful exploit could allow the attacker to prevent all incoming TCP connections to the device from being established, including remote management access, Remote Access VPN (RAVPN) connections, and all network protocols that are TCP-based. This results in a denial of service (DoS) condition for affected features. (CVE-2026-20082)

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

Solution

Upgrade to the relevant fixed version referenced in Cisco bug ID CSCwr58661

Plugin Details

Severity: High

ID: 311447

File Name: cisco-sa-asa-dos-FCvLD6vR.nasl

Version: 1.1

Type: Local

Family: CISCO

Published: 5/1/2026

Updated: 5/1/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

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-2026-20082

CVSS v3

Risk Factor: High

Base Score: 8.6

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

Vulnerability Information

CPE: cpe:/a:cisco:adaptive_security_appliance_software

Required KB Items: Host/Cisco/ASA

Patch Publication Date: 3/4/2026

Vulnerability Publication Date: 3/4/2026

Reference Information

CVE: CVE-2026-20082

CISCO-SA: cisco-sa-asa-dos-FCvLD6vR

IAVA: 2026-A-0201

CISCO-BUG-ID: CSCwr58661

Detections

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