Cisco Identity Services Engine Software REST API command injection

Summaryinfo

A vulnerability classified as very critical has been found in Cisco Identity Services Engine Software and ISE Passive Identity Connector. This impacts an unknown function of the component REST API. Performing a manipulation results in command injection. This vulnerability is identified as CVE-2026-20306. The attack can be initiated remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Identity Services Engine Software and ISE Passive Identity Connector (version now known). It has been classified as very critical. This affects some unknown processing of the component REST API. The manipulation with an unknown input leads to a command injection vulnerability. CWE is classifying the issue as CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A vulnerability in the REST API of Cisco ISE and ISE-PIC could allow an authenticated, remote attacker to perform command injection attacks on the underlying operating system and elevate privileges to root. To exploit this vulnerability, the attacker must have valid administrative credentials. This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending crafted commands 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 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 shared at sec.cloudapps.cisco.com. This vulnerability is uniquely identified as CVE-2026-20306 since 10/08/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. The exploitation needs additional levels of successful authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/16/2026). MITRE ATT&CK project uses the attack technique T1202 for this issue.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Policy Management Software

Vendor

• Cisco

Name

• Identity Services Engine Software
• ISE Passive Identity Connector

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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