CVE-2026-20211 PUBLISHED

Cisco Identity Services Engine Remote Code Execution Vulnerability

Assigner: cisco
Reserved: 08.10.2025 Published: 16.09.2026 Updated: 17.09.2026

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 condition, endpoints that have not already authenticated would be unable to access the network until the node is restored.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 9.1

Product Status

Vendor Cisco
Product Cisco Identity Services Engine Software
Versions Default: unknown
  • Version 3.1.0 is affected
  • Version 3.1.0 p1 is affected
  • Version 3.1.0 p3 is affected
  • Version 3.1.0 p2 is affected
  • Version 3.2.0 is affected
  • Version 3.1.0 p4 is affected
  • Version 3.1.0 p5 is affected
  • Version 3.2.0 p1 is affected
  • Version 3.1.0 p6 is affected
  • Version 3.2.0 p2 is affected
  • Version 3.1.0 p7 is affected
  • Version 3.3.0 is affected
  • Version 3.2.0 p3 is affected
  • Version 3.2.0 p4 is affected
  • Version 3.1.0 p8 is affected
  • Version 3.2.0 p5 is affected
  • Version 3.2.0 p6 is affected
  • Version 3.1.0 p9 is affected
  • Version 3.3 Patch 2 is affected
  • Version 3.3 Patch 1 is affected
  • Version 3.3 Patch 3 is affected
  • Version 3.4.0 is affected
  • Version 3.2.0 p7 is affected
  • Version 3.3 Patch 4 is affected
  • Version 3.4 Patch 1 is affected
  • Version 3.1.0 p10 is affected
  • Version 3.3 Patch 5 is affected
  • Version 3.3 Patch 6 is affected
  • Version 3.4 Patch 2 is affected
  • Version 3.3 Patch 7 is affected
  • Version 3.4 Patch 3 is affected
  • Version 3.5.0 is affected
  • Version 3.4 Patch 4 is affected
  • Version 3.3 Patch 8 is affected
  • Version 3.2 Patch 8 is affected
  • Version 3.5 Patch 1 is affected
  • Version 3.3 Patch 9 is affected
  • Version 3.2 Patch 9 is affected
  • Version 3.4 Patch 5 is affected
  • Version 3.5 Patch 3 is affected
  • Version 3.5 Patch 2 is affected
  • Version 3.3 Patch 10 is affected
  • Version 3.3 Patch 11 is affected
  • Version 3.4 Patch 6 is affected
  • Version 3.2 Patch 10 is affected
  • Version 3.1.0 p72 is affected
  • Version 3.1.0 p11 is affected

Exploits

The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

References

Problem Types

  • Deserialization of Untrusted Data cwe