# CVE-2026-101572: Oracle Helidon denial of service in HTTP/2 webclient

Source: https://junglewise.ai/threats/cve-2026-101572-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware  
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-2026-101572 · Severity: high · CVSS 7.5 · Published 2026-10-20

Oracle Helidon is a lightweight framework for building microservices and cloud-native applications. An unauthenticated attacker on the network can send specially crafted HTTP/2 requests to cause the application to hang or crash, resulting in a complete service outage with no user interaction required.

Technologies: [Oracle Helidon](https://junglewise.ai/threats/technologies/helidon). Vendors: [Oracle](https://junglewise.ai/threats/vendors/oracle).

## Quick answers

**Is CVE-2026-101572 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101572 being exploited in the wild.

**How severe is CVE-2026-101572?** High severity, with a CVSS score of 7.5, published 20 October 2026.

**Which products and versions are affected?** Oracle Helidon 4.0.0-4.5.5, 27.0.0.

**Is there a fix for CVE-2026-101572?** 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-2026-101572 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-101572?** Check whether you run Oracle Helidon 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

The vulnerability exists in the helidon-webclient-http2 component and can be triggered by an unauthenticated remote attacker with network access via HTTP/2 protocol. Successful exploitation results in denial of service through application hang or crash. The vulnerability requires no authentication, no user interaction, and affects Helidon versions 4.0.0 through 4.5.5 and 27.0.0.

## Affected products

- Oracle Helidon 4.0.0-4.5.5, 27.0.0

## 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 Helidon microprofile-security authentication bypass](https://junglewise.ai/threats/cve-2026-101590-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware)
- [Oracle Helidon WebSocket unauthenticated information disclosure](https://junglewise.ai/threats/cve-2026-101588-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware)
- [Oracle Helidon denial of service in webclient HTTP/1](https://junglewise.ai/threats/cve-2026-101587-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware)
- [Oracle Helidon information disclosure in helidon-webclient](https://junglewise.ai/threats/cve-2026-101586-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware)
- [Oracle Helidon CORS authorization bypass in helidon-cors](https://junglewise.ai/threats/cve-2026-101585-vulnerability-in-the-helidon-product-of-oracle-fusion-middleware)