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Vulnerability record · CVE-2026-20343 · published 16 September 2026

CVE-2026-20343: Missing authentication for critical function 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.

7.5 CVSS 3.1 High EPSS 0.45% · top 63.4% CWE-306 · Missing authentication for critical function Awaiting Analysis
7.5CVSS 3.1 base score
0.45%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
1References
18 Sep 2026Last modified by NVD

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 DoS condition.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

LinkTags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-mulivulns-4PsnFwvx

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Source: NIST National Vulnerability Database (record CVE-2026-20343), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.