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HIGH

CVE-2026-20343

CVSS v3

7.5

HIGH

EPSS Score

0.4 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

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

Technical details

Published
2026-09-16
Last Modified
2026-09-18

Frequently asked questions

What is CVE-2026-20343?

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

Is CVE-2026-20343 actively exploited?

Active exploitation of CVE-2026-20343 has not been confirmed. Its EPSS score was 0.4% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-20343?

CVE-2026-20343 has a CVSS v3 base score of 7.5 (HIGH severity).

Is CVE-2026-20343 affecting your environment?

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