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IMMUNITYSEC

CVE-2025-20333

9.9
CRITICAL
CVSS 3.1
EPSS 71.2% · 99th pctCISA KEV · Exploited in the wild
2025-09-25Updated 2026-02-26KEV 2025-09-25
CISA Known Exploited Vulnerabilities

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV
2025-09-25
Remediation due
2025-09-26

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 notes
CISA Mitigation Instructions: https://www.cisa.gov/news-events/directives/ed-25-03-identify-and-mitigate-potential-compromise-cisco-devices ; https://www.cisa.gov/news-events/directives/supplemental-direction-ed-25-03-core-dump-and-hunt-instructions ; https://www.cisa.gov/eviction-strategies-tool/create-from-template ; https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks ; https://sec.cloudapps.cisco.com/security/center/private/resources/asa_ftd_continued_attacks#Details ; https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-z5xP8EUB ; https://nvd.nist.gov/vuln/detail/CVE-2025-20333

Description

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.

Severity

CVSS 3.1 · CNA9.9 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
SSVC · CISA-ADP
Exploitationactive
Automatableno
Technical impacttotal

Exploitation Context

as of October 17, 2026
All KEV statistics→
  • CISA added CVE-2025-20333 to the KEV catalog on the day its CVE record was published. The median for entries added in 2025 is 26 days.
  • It is one of 101 Cisco entries in the CISA KEV catalog, and one of 8 added in 2025.
  • Its current EPSS score (71.2%) is higher than that of 58% of CISA KEV entries.

Affected Products

ProductAffected versions
Cisco
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
9.8.1
9.8.1.5
9.8.1.7
9.8.2
9.8.2.8
9.8.2.14
9.8.2.15
9.8.2.17
9.8.2.20
9.8.2.24
9.8.2.26
9.8.2.28
9.8.2.33
9.8.2.35
9.8.2.38
9.8.3.8
9.8.3.11
9.8.3.14
9.8.3.16
9.8.3.18
9.8.3.21
9.8.3
9.8.3.26
9.8.3.29
9.8.4
9.8.4.3
9.8.4.7
9.8.4.8
9.8.4.10
9.8.4.12
9.8.4.15
9.8.4.17
9.8.2.45
9.8.4.25
9.8.4.20
9.8.4.22
9.8.4.26
9.8.4.29
9.8.4.32
9.8.4.33
9.8.4.34
9.8.4.35
9.8.4.39
9.8.4.40
9.8.4.41
9.8.4.43
9.8.4.44
9.8.4.45
9.8.4.46
9.8.4.48
9.12.1
9.12.1.2
9.12.1.3
9.12.2
9.12.2.4
9.12.2.5
9.12.2.9
9.12.3
9.12.3.2
9.12.3.7
9.12.4
9.12.3.12
9.12.3.9
9.12.2.1
9.12.4.2
9.12.4.4
9.12.4.7
9.12.4.10
9.12.4.13
9.12.4.8
9.12.4.18
9.12.4.24
9.12.4.26
9.12.4.29
9.12.4.30
9.12.4.35
9.12.4.37
9.12.4.38
9.12.4.39
9.12.4.40
9.12.4.41
9.12.4.47
9.12.4.48
9.12.4.50
9.12.4.52
9.12.4.54
9.12.4.55
9.12.4.56
9.12.4.58
9.12.4.62
9.12.4.65
9.12.4.67
9.14.1
9.14.1.10
9.14.1.6
9.14.1.15
9.14.1.19
9.14.1.30
9.14.2
9.14.2.4
9.14.2.8
9.14.2.13
9.14.2.15
9.14.3
9.14.3.1
9.14.3.9
9.14.3.11
9.14.3.13
9.14.3.18
9.14.3.15
9.14.4
9.14.4.6
9.14.4.7
9.14.4.12
9.14.4.13
9.14.4.14
9.14.4.15
9.14.4.17
9.14.4.22
9.14.4.23
9.14.4.24
9.16.1
9.16.1.28
9.16.2
9.16.2.3
9.16.2.7
9.16.2.11
9.16.2.13
9.16.2.14
9.16.3
9.16.3.3
9.16.3.14
9.16.3.15
9.16.3.19
9.16.3.23
9.16.4
9.16.4.9
9.16.4.14
9.16.4.18
9.16.4.19
9.16.4.27
9.16.4.38
9.16.4.39
9.16.4.42
9.16.4.48
9.16.4.55
9.16.4.57
9.16.4.61
9.16.4.62
9.16.4.67
9.16.4.70
9.16.4.71
9.16.4.76
9.16.4.82
9.16.4.84
9.17.1
9.17.1.7
9.17.1.9
9.17.1.10
9.17.1.11
9.17.1.13
9.17.1.15
9.17.1.20
9.17.1.30
9.17.1.33
9.17.1.39
9.18.1
9.18.1.3
9.18.2
9.18.2.5
9.18.2.7
9.18.2.8
9.18.3
9.18.3.39
9.18.3.46
9.18.3.53
9.18.3.55
9.18.3.56
9.18.4
9.18.4.5
9.18.4.8
9.18.4.22
9.18.4.24
9.18.4.29
9.18.4.34
9.18.4.40
9.19.1
9.19.1.5
9.19.1.9
9.19.1.12
9.19.1.18
9.19.1.22
9.19.1.24
9.19.1.27
9.19.1.28
9.19.1.31
9.20.1
9.20.1.5
9.20.2
9.20.2.10
9.20.2.21
9.20.2.22
9.20.3
9.20.3.4
9.22.1.1
9.22.1.2
Cisco
Cisco Secure Firewall Threat Defense (FTD) Software
6.2.3
6.2.3.1
6.2.3.2
6.2.3.3
6.2.3.4
6.2.3.5
6.2.3.6
6.2.3.7
6.2.3.8
6.2.3.10
6.2.3.11
6.2.3.9
6.2.3.12
6.2.3.13
6.2.3.14
6.2.3.15
6.2.3.16
6.2.3.17
6.2.3.18
6.6.0
6.6.0.1
6.6.1
6.6.3
6.6.4
6.6.5
6.6.5.1
6.6.5.2
6.6.7
6.6.7.1
6.6.7.2
6.4.0
6.4.0.1
6.4.0.3
6.4.0.2
6.4.0.4
6.4.0.5
6.4.0.6
6.4.0.7
6.4.0.8
6.4.0.9
6.4.0.10
6.4.0.11
6.4.0.12
6.4.0.13
6.4.0.14
6.4.0.15
6.4.0.16
6.4.0.17
6.4.0.18
7.0.0
7.0.0.1
7.0.1
7.0.1.1
7.0.2
7.0.2.1
7.0.3
7.0.4
7.0.5
7.0.6
7.0.6.1
7.0.6.2
7.0.6.3
7.0.7
7.0.8
7.1.0
7.1.0.1
7.1.0.2
7.1.0.3
7.2.0
7.2.0.1
7.2.1
7.2.2
7.2.3
7.2.4
7.2.4.1
7.2.5
7.2.5.1
7.2.6
7.2.7
7.2.5.2
7.2.8
7.2.8.1
7.3.0
7.3.1
7.3.1.1
7.3.1.2
7.4.0
7.4.1
7.4.1.1
7.4.2
7.4.2.1
7.4.2.2
7.4.2.3
7.6.0

References

1 Links

Record Details

Published
2025-09-25
Last updated
2026-02-26
Assigner (CNA)
cisco
Credited to
-

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CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.