CVE-2020-3436

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services File Upload Denial of Service Vulnerability

HIGH
8.6
CVSS Score
Published: October 21, 2020 at 06:36 PM UTC
Updated: August 11, 2026 at 07:37 PM UTC
2 products affected across 1 vendorAdaptive Security ApplianceSecure Firewall Threat Defense

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Severity
HIGH8.6
Exploit prediction
EPSS 2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 9.6.4.459.10.0 ≤ v < 9.10.1.449.12.0 ≤ v < 9.12.4.29.13.0 ≤ v < 9.13.1.129.14.0 ≤ v < 9.14.1.159.8.0 ≤ v < 9.8.4.259.9.0 ≤ v < 9.9.2.80
Affected range stops below 9.10.1.44, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.12.4.2, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.13.1.12, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.14.1.15, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.6.4.45, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.8.4.25, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.9.2.80, so it looks safe — our inference, not a vendor statement
v ≤ 6.2.26.3.0 ≤ v < 6.3.0.66.4.0 ≤ v < 6.4.0.106.5.0 ≤ v < 6.5.0.56.6.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-434

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