# CVE-2026-20307

## Summary

- **CVE ID:** CVE-2026-20307
- **Severity:** CRITICAL
- **CVSS Score:** 9.9 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** CWE-502
- **Published:** Sep 16, 2026
- **Last Modified:** Sep 17, 2026

## 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.

## Affected Products

- Cisco — Cisco Identity Services Engine Software (3.1.0)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p1)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p3)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p2)
- Cisco — Cisco Identity Services Engine Software (3.2.0)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p4)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p5)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p1)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p6)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p2)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p7)
- Cisco — Cisco Identity Services Engine Software (3.3.0)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p3)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p4)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p8)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p5)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p6)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p9)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 2)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 1)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 3)
- Cisco — Cisco Identity Services Engine Software (3.4.0)
- Cisco — Cisco Identity Services Engine Software (3.2.0 p7)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 4)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 1)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p10)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 5)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 6)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 2)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 7)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 3)
- Cisco — Cisco Identity Services Engine Software (3.5.0)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 4)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 8)
- Cisco — Cisco Identity Services Engine Software (3.2 Patch 8)
- Cisco — Cisco Identity Services Engine Software (3.5 Patch 1)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 9)
- Cisco — Cisco Identity Services Engine Software (3.2 Patch 9)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 5)
- Cisco — Cisco Identity Services Engine Software (3.5 Patch 3)
- Cisco — Cisco Identity Services Engine Software (3.5 Patch 2)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 10)
- Cisco — Cisco Identity Services Engine Software (3.3 Patch 11)
- Cisco — Cisco Identity Services Engine Software (3.4 Patch 6)
- Cisco — Cisco Identity Services Engine Software (3.2 Patch 10)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p72)
- Cisco — Cisco Identity Services Engine Software (3.1.0 p11)

## References

- [CNA](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-rce-se7bYU57)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.95%
- **EPSS Percentile:** 59.7

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._