CVE-2025-20243Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
- 8.6HighCVSS base score
- 0.63%Exploitation in 30 daysEPSS · top 49% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the management and VPN web servers of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability is due to improper validation of user-supplied input on an interface with VPN web services. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on an affected device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.
Timeline
ID reserved
By cisco
- 10 months later
· 10 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Deferred | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.63% · top 49% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.
Affected products
Cisco · Cisco Adaptive Security Appliance (ASA) Software
- affected 9.12.3
- affected 9.8.3
- affected 9.12.1
- affected 9.8.1
- affected 9.12.2
- affected 9.8.2.45
- affected 9.8.2
- affected 9.8.4
- affected 9.14.1
- affected 9.12.4
- affected 9.8.2.26
- affected 9.8.2.24
- affected 9.8.2.15
- affected 9.8.2.14
- affected 9.8.2.35
- affected 9.8.2.20
- affected 9.8.2.8
- affected 9.8.2.17
- affected 9.8.2.28
- affected 9.8.2.33
- affected 9.8.2.38
- affected 9.8.4.25
- affected 9.12.3.2
- affected 9.12.3.7
- affected 9.8.3.18
- affected 9.8.3.14
- affected 9.8.4.15
- affected 9.8.4.8
- affected 9.8.1.7
- affected 9.8.3.29
- affected 9.14.1.10
- affected 9.12.2.5
- affected 9.8.4.22
- affected 9.12.3.12
- affected 9.8.4.7
- affected 9.8.4.17
- affected 9.8.3.16
- affected 9.8.4.20
- affected 9.8.3.11
- affected 9.12.1.3
- and 180 more
Cisco · Cisco Firepower Threat Defense Software
- affected 6.2.3.14
- affected 6.4.0.1
- affected 6.2.3.7
- affected 6.2.3
- affected 6.4.0.2
- affected 6.2.3.9
- affected 6.2.3.1
- affected 6.2.3.2
- affected 6.4.0.5
- affected 6.2.3.10
- affected 6.4.0
- affected 6.4.0.3
- affected 6.2.3.6
- affected 6.4.0.4
- affected 6.2.3.15
- affected 6.2.3.5
- affected 6.2.3.4
- affected 6.2.3.3
- affected 6.2.3.8
- affected 6.4.0.6
- affected 6.2.3.11
- affected 6.2.3.12
- affected 6.2.3.13
- affected 6.4.0.7
- affected 6.4.0.8
- affected 6.6.0
- affected 6.4.0.9
- affected 6.2.3.16
- affected 6.6.0.1
- affected 6.6.1
- affected 6.4.0.10
- affected 6.4.0.11
- affected 6.6.3
- affected 6.6.4
- affected 6.4.0.12
- affected 7.0.0
- affected 6.2.3.17
- affected 7.0.0.1
- affected 6.6.5
- affected 7.0.1
- and 54 more
What to do
Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
References
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-24845 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-20243)Record last updated .