CVE-2025-20243
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
Published Aug 14, 2025
CVSS 3.1 · 8.6 High
EPSS < 1%
KEV · Not listed
Description
A vulnerability in the management and VPN web servers of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition.
This vulnerability is due to improper validation of user-supplied input on an interface with VPN web services. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on an affected device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.
This vulnerability is due to improper validation of user-supplied input on an interface with VPN web services. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on an affected device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Cisco | Cisco Adaptive Security Appliance (ASA) Software | unknown |
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| Cisco | Cisco Firepower Threat Defense Software | unknown |
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No data.
No data.
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Adaptive Security Appliance Software | — |
| Cisco | Firepower Threat Defense Software | — |
Remediation
Tracking
Advisories
| Source | ID | Title |
|---|---|---|
 EUVD |
EUVD-2025-24845 | A vulnerability in the management and VPN web servers of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability is due to improper validation of user-supplied input on an interface with VPN web services. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on an affected device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads. |
Metrics
No CVSS v4.0
Attack Vector Network
Attack Complexity Low
Privileges Required None
Scope Changed
Confidentiality Impact None
Integrity Impact None
Availability Impact High
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.631% probability within 30 days)
Exploitation none
Automatable yes
Technical Impact partial
References
History
Aug 15, 2025 8:15 AM
First appearance in the feed. Affected vendors updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Cisco
Cisco adaptive Security Appliance Software Cisco firepower Threat Defense Software |
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| Vendors & Products |
Cisco
Cisco adaptive Security Appliance Software Cisco firepower Threat Defense Software |
Aug 14, 2025 8:15 PM
Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Aug 14, 2025 4:45 PM
Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A vulnerability in the management and VPN web servers of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability is due to improper validation of user-supplied input on an interface with VPN web services. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on an affected device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads. | |
| Title | Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability | |
| Weaknesses | CWE-835 | |
| References |
| |
| Metrics |
cvssV3_1
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Subscriptions
Weaknesses
