# CVE-2026-91390: Oracle Siebel CRM End User cross-site request forgery in Open UI

Source: https://junglewise.ai/threats/cve-2026-91390-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-2026-91390 · Severity: medium · CVSS 5.4 · Published 2026-10-20

Oracle Siebel CRM End User is a customer relationship management platform used by enterprises to manage sales and customer interactions. A vulnerability in the Open UI component allows an authenticated attacker to perform unauthorized modifications and read sensitive data by tricking another user into clicking a malicious link, potentially compromising customer records and business-critical information.

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-2026-91390 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91390 being exploited in the wild.

**How severe is CVE-2026-91390?** 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-2026-91390?** 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-2026-91390 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-91390?** 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 network-accessible vulnerability in the Open UI component of Siebel CRM End User allows a low-privileged authenticated attacker to conduct a cross-site request forgery (CSRF) attack with user interaction. The vulnerability enables unauthorized updates, inserts, deletes, and reads of data accessible to the victim user, with potential scope change affecting related systems. The vulnerability affects versions 17.0 through 26.9.

## 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)