# CVE-2026-20307: Cisco Identity Services Engine RCE via deserialization in management interface

Source: https://junglewise.ai/threats/cve-2026-20307-cisco-identity-services-engine-rce-via-deserialization-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-16. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-20307 · Severity: critical · CVSS 9.9 · Published 2026-09-16

Cisco Identity Services Engine (ISE) is a network access control solution used to authenticate and manage devices connecting to corporate networks. A critical flaw in its web-based management interface allows authenticated administrators with low privileges to execute arbitrary code on the device and gain root access. Successful exploitation could also render single-node ISE deployments unavailable, preventing network access for unauthenticated endpoints until service is restored.

Technologies: [Cisco Identity Services Engine](https://junglewise.ai/threats/technologies/identity-services-engine). Vendors: [Cisco](https://junglewise.ai/threats/vendors/cisco).

## Quick answers

**Is CVE-2026-20307 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20307 being exploited in the wild.

**How severe is CVE-2026-20307?** Critical severity, with a CVSS score of 9.9, published 16 September 2026.

**Which products and versions are affected?** Cisco Identity Services Engine.

**Is there a fix for CVE-2026-20307?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-20307 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-20307?** Check whether you run Cisco Identity Services Engine. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

CVE-2026-20307 is an insecure Java deserialization vulnerability (CWE-502) in Cisco ISE's web-based management interface. An attacker with low-privileged administrative credentials can exploit this by sending a crafted serialized Java object to the affected device. The vulnerability allows remote, unauthenticated code execution with no user interaction required (CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H). A successful exploit grants arbitrary code execution and privilege escalation to root, potentially causing complete device compromise or denial of service in single-node deployments. Cisco has released software updates to address this vulnerability; no workarounds are available.

## Affected products

- Cisco Identity Services Engine

## Timeline

- 2026-09-16: disclosed

## References

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

## Related threats

- [Cisco Identity Services Engine authorization bypass in management interface](https://junglewise.ai/threats/cve-2026-20183-a-vulnerability-in-the-web-based-management-interface-of-cisco)
- [Cisco Identity Services Engine authorization bypass in certificate enrollment](https://junglewise.ai/threats/cve-2026-20241-a-vulnerability-in-the-authorization-mechanism-of-cisco-identity)
- [A vulnerability in an API of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to bypass authentication.](https://junglewise.ai/threats/cve-2026-76460-cisco-identity-services-engine-incorrect-privileged-api-use)
- [Cisco ISE SQL and HQL injection in APIs](https://junglewise.ai/threats/cve-2026-76451-cisco-ise-sql-and-hql-injection-in-apis)
- [Cisco Identity Services Engine SQL and HQL injection](https://junglewise.ai/threats/cve-2026-76450-cisco-identity-services-engine-sql-and-hql-injection)