CVE-2020-3436
No exploitation reported by the sources we read.
- Published2020-10-21
- Fixed in9.14.1.15 · 9.13.1.12 · 9.12.4.2 · 9.10.1.44 · 9.9.2.80 · 9.8.4.25
- WeaknessCWE-434
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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
dates in UTC- 2020-10-2119:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-3436?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-3436?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.14 | ≥ 9.14.0, < 9.14.1.15 | 9.14.1.15 | NVD |
| 9.13 | ≥ 9.13.0, < 9.13.1.12 | 9.13.1.12 | NVD |
| 9.12 | ≥ 9.12.0, < 9.12.4.2 | 9.12.4.2 | NVD |
| 9.10 | ≥ 9.10.0, < 9.10.1.44 | 9.10.1.44 | NVD |
| 9.9 | ≥ 9.9.0, < 9.9.2.80 | 9.9.2.80 | NVD |
| 9.8 | ≥ 9.8.0, < 9.8.4.25 | 9.8.4.25 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 6.5 | ≥ 6.5.0, < 6.5.0.5 | 6.5.0.5 | NVD |
| 6.4 | ≥ 6.4.0, < 6.4.0.10 | 6.4.0.10 | NVD |
| 6.3 | ≥ 6.3.0, < 6.3.0.6 | 6.3.0.6 | NVD |
| 6.2 | ≤ 6.2.2 | no fix published | NVD |
| 6.6 | = 6.6.0 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.6 | < 9.6.4.45 | 9.6.4.45 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Cisco ASA to 9.14.1.15 · 9.13.1.12 · 9.12.4.2 · 9.10.1.44 · 9.9.2.80 · 9.8.4.25
Advisories and patches
- tools.cisco.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- Published
- 2020-10-21
- Last Modified
- 2026-08-11
- NVD status
- Modified
Frequently asked questions
What is CVE-2020-3436?
Is CVE-2020-3436 actively exploited?
What is the CVSS score for CVE-2020-3436?
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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.