Search/CVE-2026-20211
CVE — Critical

CVE-2026-20211

A vulnerability in Cisco ISE could allow an authenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. To exploit this vulnerability, the attacker must have valid high-privileged administrative credentials. This vulnerability is due to insecure deserialization of Java objects by the affected software. An attacker could exploit this vulnerability by sending a crafted serialized Java object to an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root. In single-node deployments, successful exploitation of this vulnerability could cause the affected ISE node to become unavailable, resulting in a DoS condition. In that…

CVSS v3.1
9.1 CRITICAL
EPSS
%
probability of exploitation in 30 days
CISA KEV
Not listed
no confirmed exploitation reported
News coverage
2
sources referencing this CVE
CVSS v3.1 Detail
Attack VectorNETWORK
Attack ComplexityLOW
Privileges RequiredHIGH
User InteractionNONE
ScopeCHANGED
ConfidentialityHIGH
IntegrityHIGH
AvailabilityHIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Connections
4 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
Sep 17, 2026
bleepingcomputer.com reports: Cisco warns of max severity ISE zero-day exploited in attacks