How severe is CVE-2025-20243?

CVE-2025-20243 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-20243 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-20243?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-20243 have an EU (EUVD) identifier?

Yes. CVE-2025-20243 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-24845.

When was CVE-2025-20243 published?

CVE-2025-20243 was published on 2025-08-14 and last updated on 2026-06-17.

CVE-2025-20243

CVE-2025-20243 is a high-severity vulnerability with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-835.

Key facts

Severity: High (CVSS 3.x base score 8.6)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-24845
Weakness: CWE-835
Published: 2025-08-14
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-20243?: 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.
How severe is CVE-2025-20243?: CVE-2025-20243 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-20243 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-20243?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-20243 have an EU (EUVD) identifier?: Yes. CVE-2025-20243 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-24845.
When was CVE-2025-20243 published?: CVE-2025-20243 was published on 2025-08-14 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-dos-mfPekA6e

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