CVE-2026-20211 Cisco ISE - Remote Code Execution & Denial of Service

Cisco ISE contains an insecure deserialization vulnerability caused by processing crafted serialized Java objects, letting authenticated remote attackers with high-privileged admin credentials execute arbitrary commands and cause DoS.

CVSS base score 9.1 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.56% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Remote Code Execution
Impact
Remote Code Execution, Privilege Escalation, Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Published
16 September 2026
Updated
15 October 2026
Weakness
CWE-502

Vendor fix

Update to the latest Cisco ISE version with the deserialization vulnerability fixed.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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