Unauthorized Download & Disk DoS in Cisco Secure FMC API
CVE-2026-20343 Published on September 16, 2026

Cisco Secure Firewall Management Center Software Information Disclosure and Disk Denial of Service Vulnerability
A vulnerability in a critical API for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to download sensitive files and use unbounded disk space. This vulnerability exists because a critical API lacks authentication. An attacker could exploit this vulnerability by repeatedly invoking the API. A successful exploit could allow the attacker to download sensitive files that should be restricted and consume disk space so the device could become unresponsive, causing a DoS condition.

NVD

Vulnerability Analysis

CVE-2026-20343 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Weakness Type

Missing Authentication for Critical Function

The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.


Products Associated with CVE-2026-20343

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Cisco Secure Firewall Management Center
 

Affected Versions

Cisco Secure Firewall Management Center (FMC):