Cisco Identity Services Engine Software up to 3.5.0 Web-based Management Interface deserialization

Summaryinfo

A vulnerability classified as very critical was found in Cisco Identity Services Engine Software. Affected is an unknown function of the component Web-based Management Interface. Executing a manipulation can lead to deserialization. This vulnerability is tracked as CVE-2026-20307. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Cisco Identity Services Engine Software. It has been declared as very critical. This vulnerability affects an unknown function of the component Web-based Management Interface. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A vulnerability in the web-based management interface of 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 at least low-privileged administrative credentials. This vulnerability is due to insecure deserialization of a user-supplied Java byte stream. An attacker could exploit this vulnerability by sending a crafted serialized Java object to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the device and 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 denial of service (DoS) condition. In that condition, endpoints that have not already authenticated would be unable to access the network until the node is restored.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability was named CVE-2026-20307 since 10/08/2025. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/16/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Policy Management Software

Vendor

• Cisco

Name

• Identity Services Engine Software

Version

• 3.1.0
• 3.1.0 p1
• 3.1.0 p2
• 3.1.0 p3
• 3.1.0 p4
• 3.1.0 p5
• 3.1.0 p6
• 3.1.0 p7
• 3.1.0 p8
• 3.1.0 p9
• 3.1.0 p10
• 3.1.0 p11
• 3.1.0 p72
• 3.2.0
• 3.2.0 p1
• 3.2.0 p2
• 3.2.0 p3
• 3.2.0 p4
• 3.2.0 p5
• 3.2.0 p6
• 3.2.0 p7
• 3.3.0
• 3.4.0
• 3.5.0

License

• commercial

Website

• Vendor: https://www.cisco.com/

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