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NVD
In CISA KEV9.9 CriticalCWE-120
CVE-2025-20333

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

CiscoSecure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense

Status
  • Exploited in the wild
  • In CISA KEV since 25 Sep 2025
  • Vendor fix available
  • Associated threat actor: Storm-1849
Federal deadlineFri 26 Sep 2025, 23:59 UTC

Passed 393 days ago

CISA KEV · added 25 Sep 2025

Exploit probabilityEPSSchecked 25 Oct
71%probability of exploitation in the next 30 days

Higher than 99% of scored CVEs

SeverityCVSS
9.9Critical

Description NVD

A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.

CISA 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.

Coverage 3 articles · 3 outlets

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CVE-2025-20333 coverage
Published (UTC)OutletHeadline
Fri 24 Apr · 11:30 UTCSecurityWeekUS Agency Hit by Firestarter Backdoor on Cisco Firepower Gear
Fri 24 Apr · 18:06 UTCThe Hacker NewsCisco ASA Backdoor FIRESTARTER Persists After Patches, NCSC Warns
Sat 25 Apr · 01:26 UTCSecurity AffairsFIRESTARTER backdoor persists on patched Cisco ASA devices
First in our coverage: SecurityWeek, 24 AprRSS feed
  1. FIRESTARTER backdoor persists on patched Cisco ASA devicesSecurity Affairs
  2. Cisco ASA Backdoor FIRESTARTER Persists After Patches, NCSC WarnsThe Hacker News
  3. US Agency Hit by Firestarter Backdoor on Cisco Firepower GearSecurityWeek · first in our coverage

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