CVE-2025-20135
Cisco Adaptive Security Appliance and Firepower Threat Defense Software DHCP Denial of Service Vulnerability
- 4.3MediumCVSS base score
- 0.22%Exploitation in 30 daysEPSS · top 88% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the DHCP client functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to exhaust available memory. This vulnerability is due to improper validation of incoming DHCP packets. An attacker could exploit this vulnerability by repeatedly sending crafted DHCPv4 packets to an affected device. A successful exploit could allow the attacker to exhaust available memory, which would affect availability of services and prevent new processes from starting, resulting in a Denial of Service (DoS) condition that would require a manual reboot. Note: On Cisco Secure FTD Software, this vulnerability does not affect management interfaces.
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 | Medium4.3 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Deferred | 3.1 | Medium4.3 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 0.22% · top 88% of all CVEs (11 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.
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 169 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 51 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 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-2025-24853 (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-2025-20135)Record last updated .