CVE-2020-3436Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services File Upload Denial of Service Vulnerability
- 8.6HighCVSS base score
- 1.9%Exploitation in 30 daysEPSS · top 20% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to upload arbitrary-sized files to specific folders on an affected device, which could lead to an unexpected device reload. The vulnerability exists because the affected software does not efficiently handle the writing of large files to specific folders on the local file system. An attacker could exploit this vulnerability by uploading files to those specific folders. A successful exploit could allow the attacker to write a file that triggers a watchdog timeout, which would cause the device to unexpectedly reload, causing a denial of service (DoS) condition.
Timeline
ID reserved
By cisco
- 10 months later
· 10 months later
Published
- 4 years later
· 4 years 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) | 3.0 | High8.6 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Modified | 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)
- 1.9% · top 20% of all CVEs (14 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 n/a
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
References1
- 20201021 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services File Upload Denial of Service Vulnerability (opens in a new tab)vendor-advisoryx_refsource_CISCOx_transferred
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-2020-24707 (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-2020-3436)Record last updated .