High severity · published Sep 16, 2026
CVE-2026-20250
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software for Firepower 3100 and 4200 Series DTLS Denial of Service Vulnerability
8.6
CVSS
0.6%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 47% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CS
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · Cisco
9.23.1; 9.22.1.1; 9.22.1.3; 9.22.1.6; 9.22.2; 9.23.1.3; +11 more · source: vendor
CS
Cisco Secure Firewall Threat Defense (FTD) Software · Cisco
7.6.0; 7.7.0; 7.6.1; 7.6.2; 7.7.10; 7.7.11; +4 more · source: vendor
Affected product
CS
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
Cisco
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