Cisco Identity Services Engine AlarmMessageDiskQueue Deserialization of Untrusted Data Remote Code Execution Vulnerability

September 18th, 2026
ZDI-26-717 ZDI-CAN-31320

CVE ID

CVE-2026-20211

CVSS Score

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

Affected Vendors

Cisco

Affected Products

Identity Services Engine

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Cisco Identity Services Engine. Authentication is required to exploit this vulnerability.

The specific flaw exists within the AlarmMessageDiskQueue class. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the iseadminportal user.

Additional Details

Cisco has issued an update to correct this vulnerability. More details can be found at:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-rce-se7bYU57

Disclosure Timeline

  • 2026-05-28 - Vulnerability reported to vendor
  • 2026-09-18 - Coordinated public release of advisory
  • 2026-09-18 - Advisory Updated

Credit

Jonathan Lein of TrendAI Research

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