Skip to content
All vulnerabilities
CVE-2026-20349KEV

Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability

Severity
High8.6CVSS 3.1, High
EPSS
1%
Published
11 Aug 2026
Updated
16 Sept 2026

Description

Title, description and vendor guidance are quoted from the source records.

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.

Weakness: CWE-244

Known exploited

Added to CISA KEV on 11 Aug 2026

Federal remediation due date: 14 Aug 2026

Required action: 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.

Exploit prediction

1% probability of exploitation in the next 30 days (percentile 62%).

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

Patcharo shows this vulnerability for information but does not match versions for this product yet.

  • Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · 9.16.1, 9.16.1.28, 9.16.2, 9.16.2.3, 9.16.2.7, 9.16.2.11, 9.16.2.13, 9.16.2.14, 9.16.3.3, 9.16.3, 9.16.3.14, 9.18.1 and 120 more
  • Cisco Cisco Secure Firewall Threat Defense (FTD) Software · 7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.2.0, 7.0.2.1, 7.0.3, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5 and 49 more

References

Provenance

Every fact on this page comes from the sources below. Nothing is written by an AI.

Cisco (CVE record)
Cisco (CVE record) · 27 Sept 2026, 23:46 UTC · Parser patcharo-cve5/1.1.0
CISA Known Exploited Vulnerabilities
CISA Known Exploited Vulnerabilities · 27 Sept 2026, 23:42 UTC · Parser patcharo-kev/1.0.0
NVD
NVD · 27 Sept 2026, 23:44 UTC · Parser patcharo-nvd/1.0.0
FIRST EPSS
FIRST EPSS · 27 Sept 2026, 23:46 UTC · Parser patcharo-epss/1.0.0

Last verified: 28 Sept 2026, 02:31 UTC