CVE-2025-20333
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense
Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Software VPN Web Server contain a buffer overflow vulnerability that allows for remote code execution. This vulnerability could be chained with CVE-2025-20362.
Exploitation status
- CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
- US federal civilian agencies are required to remediate it by 2025-09-26. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.
Required action
The KEV due date refers to the deadline by which FCEB agencies are expected to review and begin implementing the guidance outlined in Emergency Directive (ED) 25-03 (URL listed below in Notes). Agencies must follow the mitigation steps provided by CISA (URL listed below in Notes) and vendor’s instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
CISA’s wording, unedited.
Scoring
- CVSS
- Not yet scored
Dates
- Published
- 2025-09-25
- Added to KEV
- 2025-09-25
- Remediation due
- 2025-09-26
- Sources
- CISA KEV