Search/CVE-2026-20343
CVE — High

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 DoS condition.

CVSS v3.1
7.5 HIGH
EPSS
%
probability of exploitation in 30 days
CISA KEV
Not listed
no confirmed exploitation reported
News coverage
1
sources referencing this CVE
CVSS v3.1 Detail
Attack VectorNETWORK
Attack ComplexityLOW
Privileges RequiredNONE
User InteractionNONE
ScopeUNCHANGED
ConfidentialityNONE
IntegrityNONE
AvailabilityHIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Connections
2 relationships
Timeline
disclosure → media coverage
Sep 16, 2026
Disclosure — published as a CVE record.
Sep 17, 2026
thehackernews.com reports: Cisco Warns of New Zero-Day ISE Auth Bypass (CVSS 10.0) Exploited in Active Attacks