CVE-2025-20134
Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability
- 8.6HighCVSS base score
- 0.43%Exploitation in 30 daysEPSS · top 62% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the certificate processing of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Timeline
ID reserved
By cisco
- 10 months later
· 10 months later
Published
- 5 days later
· 5 days later
Record updated
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)
- 0.43% · top 62% of all CVEs (12 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 9.12.4.39
- affected 9.12.4.40
- affected 9.14.4.6
- affected 9.14.4.7
- affected 9.12.4.41
- affected 9.12.4.47
- affected 9.14.4.12
- affected 9.12.4.48
- affected 9.14.4.13
- affected 9.12.4.50
- affected 9.14.4.14
- affected 9.12.4.52
- affected 9.14.4.15
- affected 9.12.4.54
- affected 9.14.4.17
- affected 9.12.4.55
- affected 9.14.4.22
- affected 9.14.4.23
- affected 9.12.4.56
- affected 9.12.4.58
- affected 9.12.4.62
- affected 9.12.4.65
- affected 9.12.4.67
- affected 9.14.4.24
Cisco · Cisco Firepower Threat Defense Software
- affected 6.6.5.2
- affected 6.4.0.15
- affected 6.6.7
- affected 6.4.0.16
- affected 6.6.7.1
- affected 6.4.0.17
- affected 6.6.7.2
- affected 6.4.0.18
What to do
Exploitation: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is 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-2025-24856 (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-2025-20134)Record last updated .