Critical severity · published Sep 16, 2026
CVE-2026-20307
Cisco Identity Services Engine Remote Code Execution Vulnerability
9.9
CVSS
1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 62% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CI
Cisco Identity Services Engine Software · Cisco
3.1.0; 3.1.0 p1; 3.1.0 p3; 3.1.0 p2; 3.2.0; 3.1.0 p4; +34 more · source: vendor
Affected product
CI
Cisco Identity Services Engine Software
Cisco
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20307
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20307
sec.cloudapps.cisco.com
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-rce-se7bYU57
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