Quick answers
- Is CVE-2026-91421 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-91421 being exploited in the wild.
- How severe is CVE-2026-91421?
- Medium severity, with a CVSS score of 5.9, published 20 October 2026.
- Which products and versions are affected?
- Oracle Siebel CRM Deployment 17.0 through 26.9.
- Is there a fix for CVE-2026-91421?
- 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-2026-91421 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-91421?
- Check whether you run Oracle Siebel CRM Deployment 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
An unauthenticated denial-of-service vulnerability in the Siebel CRM Deployment Server Infrastructure component is exploitable over HTTP with high complexity. The attack requires network access and causes the application to hang or crash, resulting in availability impact. No authentication or user interaction is required.
Affected products
- Oracle Siebel CRM Deployment 17.0 through 26.9
Timeline
- 2026-10-20: disclosed