# CVE-2026-91396: Oracle Java SE integrity and availability vulnerability in Utility

Source: https://junglewise.ai/threats/cve-2026-91396-vulnerability-in-the-oracle-java-se-oracle-graalvm-for-jdk-oracle  
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-2026-91396 · Severity: medium · CVSS 6.5 · Published 2026-10-20

A vulnerability in Oracle Java SE, GraalVM for JDK, and GraalVM Enterprise Edition allows unauthenticated attackers to compromise data integrity and availability through network-accessible APIs. An attacker could modify or delete accessible data and trigger partial denial of service without authentication, particularly in web services that process untrusted data or in sandboxed Java applets running untrusted code from the internet.

Technologies: [Oracle GraalVM Enterprise Edition](https://junglewise.ai/threats/technologies/graalvm-enterprise-edition), [Oracle Graalvm For Jdk](https://junglewise.ai/threats/technologies/graalvm-for-jdk), [Oracle Java SE](https://junglewise.ai/threats/technologies/java-se). Vendors: [Oracle](https://junglewise.ai/threats/vendors/oracle).

## Quick answers

**Is CVE-2026-91396 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91396 being exploited in the wild.

**How severe is CVE-2026-91396?** Medium severity, with a CVSS score of 6.5, published 20 October 2026.

**Which products and versions are affected?** Oracle GraalVM Enterprise Edition 21.3.19.1.1; Oracle Graalvm For Jdk 17.0.20.1, 21.0.12.1; Oracle Java SE 8u503, 8u503-perf, 11.0.32.1.

**Is there a fix for CVE-2026-91396?** 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-2026-91396 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-91396?** Check whether you run Oracle GraalVM Enterprise Edition, Oracle Graalvm For Jdk or Oracle Java SE 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 Utility component in Java SE and GraalVM products contains an easily exploitable vulnerability allowing unauthenticated network access via multiple protocols. Attackers can invoke vulnerable APIs—including through web services—to achieve unauthorized data modification or deletion and partial denial of service. The vulnerability affects Java sandboxed execution environments where untrusted code may be loaded.

## Affected products

- Oracle Java SE 8u503, 8u503-perf, 11.0.32.1
- Oracle GraalVM for JDK 17.0.20.1, 21.0.12.1
- Oracle GraalVM Enterprise Edition 21.3.19.1.1

## Timeline

- 2026-10-20: disclosed

## References

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

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