Risk Letters

Exploited vulnerability

CVE-2025-20333

TLP:CLEAR

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability

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.

Facts

  • Vendor: Cisco
  • Product: Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense
  • CVSS: 9.9
  • EPSS (probability of exploitation within 30 days): 71.2 %
  • On CISA's Known Exploited Vulnerabilities list since: 25 September 2025
  • First known exploitation: 25 September 2025
  • CISA's deadline for US federal agencies: 26 September 2025
  • Weakness: CWE-120
  • First seen by Risk Letters: 25 September 2025

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD