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8.6 High Exploited

CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability

Active exploitation observed

· CISA KEV catalogue
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.
Ransomware campaigns Not observed so far
Weakness CWE-244

Description

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.

Affected products and versions

Product Affected versions Fixed in
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.24 9.24.1 → 9.24.1.155 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.23 9.23.1 → 9.23.1.195 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 9.22.1.1 → 9.22.3.5 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 9.20.1 → 9.20.4.34 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 9.19.1 → 9.19.1.42 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 9.18.1 → 9.18.4.135 No fix stated
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 9.16.1 → 9.16.4.92 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 10.0 10.0.0 → 10.0.2 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 7.7 7.7.0 → 7.7.11 No fix stated
Show the 5 other branches
Product Affected versions Fixed in
Cisco Secure Firewall Threat Defense (FTD) Software 7.6 7.6.0 → 7.6.4 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 7.4 7.4.0 → 7.4.7 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 7.3 7.3.0 → 7.3.1.2 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 7.2 7.2.0 → 7.2.11 No fix stated
Cisco Secure Firewall Threat Defense (FTD) Software 7.0 7.0.0 → 7.0.9 No fix stated

References

Timeline

  1. Published
  2. Added to the KEV catalogue
  3. Last modified

Other CVEs of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

The 48 CVEs of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software →
CVE-2026-76418 Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability 8.6 High CVE-2026-20121 A vulnerability in the access control list (ACL) Object Group Search (OGS) implementation of Cisco Secure Firewall… 5.3 Medium CVE-2026-20120 A vulnerability in the access control list (ACL) Object Group Search (OGS) implementation of Cisco Secure Firewall… 5.8 Medium CVE-2026-20248 A vulnerability in the DNS over TCP implementation of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software… 6.8 Medium
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