ACTIVELY EXPLOITED
CVE-2025-20333: Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability
| Vendor | Cisco |
|---|---|
| Product | Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense |
| Actively exploited | Yes |
| Added to CISA KEV | 25 Sep 2025 |
| CISA federal deadline | 26 Sep 2025 |
| Weakness (CWE) | CWE-120 |
Required action (CISA's text)
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.
Description (NVD)
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.
SOURCES
Other Cisco flaws
- CVE-2026-20320: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability
- CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
- CVE-2026-76519: Cisco Secure Email Gateway Relative Path Traversal Vulnerability
- CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
- CVE-2026-76460: Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.