# CVE-2026-91389: Oracle Siebel CRM End User authorization bypass in Open UI

Source: https://junglewise.ai/threats/cve-2026-91389-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-20. Updated: 2026-10-20  
License: CC BY 4.0 with a link back

CVE-2026-91389 · Severity: medium · CVSS 5.4 · Published 2026-10-20

Oracle Siebel CRM is a customer relationship management system that stores sensitive business data including customer records and transaction history. This vulnerability allows a low-privileged user to read, modify, or delete data they should not have access to if they can trick another user into interacting with a malicious request. The attack can affect other connected systems beyond Siebel itself.

Technologies: [Oracle Siebel CRM End User](https://junglewise.ai/threats/technologies/siebel-crm-end-user). Vendors: [Oracle](https://junglewise.ai/threats/vendors/oracle).

## Quick answers

**Is CVE-2026-91389 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91389 being exploited in the wild.

**How severe is CVE-2026-91389?** Medium severity, with a CVSS score of 5.4, published 20 October 2026.

**Which products and versions are affected?** Oracle Siebel CRM End User 17.0-26.9.

**Is there a fix for CVE-2026-91389?** 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-2026-91389 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-91389?** Check whether you run Oracle Siebel CRM End User at an affected version. 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

A privilege escalation vulnerability exists in the Open UI component of Siebel CRM End User, where insufficient access controls allow low-privileged attackers with network access to perform unauthorized data operations through HTTP requests. Exploitation requires user interaction (likely a clickjacking or CSRF scenario) but results in unauthorized read, update, insert, or delete access to CRM data with potential scope change to downstream systems. No indication of a publicly available exploit or patch status.

## Affected products

- Oracle Siebel CRM End User 17.0-26.9

## Timeline

- 2026-10-20: disclosed

## References

- [https://www.oracle.com/security-alerts/cpuoct2026.html](https://www.oracle.com/security-alerts/cpuoct2026.html)

## Related threats

- [Oracle Siebel CRM End User unauthorized data access in Communications Panel](https://junglewise.ai/threats/cve-2026-91445-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel)
- [Oracle Siebel CRM End User unauthorized data access in Open UI](https://junglewise.ai/threats/cve-2026-91432-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel)
- [Oracle Siebel CRM End User unauthorized data access in Open UI](https://junglewise.ai/threats/cve-2026-91431-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel)
- [Oracle Siebel CRM End User Cross-Site Request Forgery in Open UI](https://junglewise.ai/threats/cve-2026-91428-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel)
- [Oracle Siebel CRM End User unauthorized access in Open UI](https://junglewise.ai/threats/cve-2026-91412-vulnerability-in-the-siebel-crm-end-user-product-of-oracle-siebel)