CVE-2026-20250 is a vulnerability in Cisco Adaptive Security Appliance
Published on September 16, 2026
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software for Firepower 3100 and 4200 Series DTLS Denial of Service Vulnerability
A vulnerability in Datagram TLS (DTLS) message handling of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Secure Firewall 3100 Series and 4200 Series devices could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to improper resource management when processing certain DTLS messages. An attacker could exploit this vulnerability by sending a crafted stream of DTLS traffic to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Vulnerability Analysis
CVE-2026-20250 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
Missing Release of Resource after Effective Lifetime
The software does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. When a resource is not released after use, it can allow attackers to cause a denial of service by causing the allocation of resources without triggering their release. Frequently-affected resources include memory, CPU, disk space, power or battery, etc.
Products Associated with CVE-2026-20250
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Affected Versions
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software:- Version 9.23.1 is affected.
- Version 9.22.1.1 is affected.
- Version 9.22.1.3 is affected.
- Version 9.22.1.6 is affected.
- Version 9.22.2 is affected.
- Version 9.23.1.3 is affected.
- Version 9.22.2.4 is affected.
- Version 9.23.1.7 is affected.
- Version 9.22.2.9 is affected.
- Version 9.23.1.13 is affected.
- Version 9.22.2.13 is affected.
- Version 9.23.1.19 is affected.
- Version 9.22.2.14 is affected.
- Version 9.24.1 is affected.
- Version 9.23.1.22 is affected.
- Version 9.22.2.20 is affected.
- Version 9.23.1.26 is affected.
- Version 7.6.0 is affected.
- Version 7.7.0 is affected.
- Version 7.6.1 is affected.
- Version 7.6.2 is affected.
- Version 7.7.10 is affected.
- Version 7.7.11 is affected.
- Version 7.6.2.1 is affected.
- Version 7.7.10.1 is affected.
- Version 7.6.4 is affected.
- Version 10.0.0 is affected.