CVE-2026-20349

Cisco — Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability

Cisco · CWE-244 · in CISA KEV since 2026-08-11

CISA federal deadline · Overdue by 2 monthsCISA KEVActively Exploited

EVRS 75 of 100 Urgent

Patch This Cycle

Rank 1,303 of 2,960 tracked

Raised to the floor for a confirmed exploited vulnerability.

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Why it scores 75

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and an EPSS probability of 0.010.

CISA KEVApplied
RansomwareDid not apply
Vendor exploitationDid not apply
EPSSApplied
Microsoft Exploitability IndexNot applicable
Pre-patch disclosureNo data
KEV recencyApplied
CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

Patch or fixed version identified

CISA required action

Fixed in

Cisco Firepower 2100 Series -> 7.0

Affected versions

secure firewall threat defense7.0.07.0.0.17.0.17.0.1.17.0.27.0.2.17.0.37.0.47.0.57.0.67.0.6.17.0.6.27.0.6.37.0.77.0.87.0.8.17.0.97.2.07.2.0.17.2.17.2.27.2.37.2.47.2.4.17.2.57.2.5.17.2.5.27.2.67.2.77.2.87.2.8.17.2.97.2.107.2.10.27.2.117.2.127.3.07.3.17.3.1.17.3.1.27.4.07.4.17.4.1.17.4.27.4.2.17.4.2.27.4.2.37.4.2.47.4.37.4.47.4.77.4.87.6.07.6.17.6.27.6.2.17.6.47.7.07.7.107.7.10.17.7.117.7.1310.0.010.0.2
adaptive security appliance software9.16.19.16.1.289.16.29.16.2.39.16.2.79.16.2.119.16.2.139.16.2.149.16.39.16.3.39.16.3.149.16.3.159.16.3.199.16.3.239.16.49.16.4.99.16.4.149.16.4.199.16.4.279.16.4.389.16.4.399.16.4.429.16.4.489.16.4.559.16.4.579.16.4.619.16.4.629.16.4.679.16.4.709.16.4.719.16.4.769.16.4.829.16.4.849.16.4.859.16.4.899.16.4.929.18.19.18.1.39.18.29.18.2.59.18.2.79.18.2.89.18.39.18.3.399.18.3.469.18.3.539.18.3.559.18.3.569.18.49.18.4.59.18.4.89.18.4.229.18.4.249.18.4.299.18.4.349.18.4.409.18.4.479.18.4.509.18.4.529.18.4.539.18.4.579.18.4.669.18.4.679.18.4.689.18.4.719.18.4.769.18.4.829.18.4.909.18.4.1359.19.19.19.1.59.19.1.99.19.1.129.19.1.189.19.1.229.19.1.249.19.1.279.19.1.289.19.1.319.19.1.379.19.1.389.19.1.429.20.19.20.1.59.20.29.20.2.109.20.2.219.20.2.229.20.39.20.3.49.20.3.79.20.3.99.20.3.109.20.3.139.20.3.169.20.3.209.20.49.20.4.79.20.4.109.20.4.149.20.4.199.20.4.229.20.4.289.20.4.309.20.4.349.20.4.469.22.1.19.22.1.29.22.1.39.22.1.69.22.29.22.2.49.22.2.99.22.2.139.22.2.149.22.2.209.22.2.329.22.39.22.3.59.23.19.23.1.39.23.1.79.23.1.139.23.1.199.23.1.229.23.1.269.23.1.329.23.1.1959.24.19.24.1.59.24.1.99.24.1.119.24.1.155

Remediation

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Fixed versions from NVD.

Evidence

Each value with its source

Measure	Value	Source
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is.	8.6	NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs.	0.010 (62.8th pctl)	FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild.	Confirmed	CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it.	Unknown or none	CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it.	2026-08-14 · CISA federal deadline · Overdue by 2 months	CISA KEV
Public exploit moduleA module existing is not the same as active exploitation.	None known	Metasploit
EUVD cross-referenceENISA's record: CVSS 8.6 (v3.1), assigned by cisco.	Listed	ENISA EUVD

Description

NVD

A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.  This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

What CISA says to do