# CVE-2026-91462: Oracle Java SE JGSS integrity bypass

Source: https://junglewise.ai/threats/cve-2026-91462-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-2026-91462 · Severity: medium · CVSS 5.9 · Published 2026-10-20

Oracle Java SE and GraalVM include a Java authentication and security library (JGSS) that is used by applications to secure communications. An unauthenticated network attacker can exploit this vulnerability by sending specially crafted data to applications using JGSS APIs, potentially allowing unauthorized modification or deletion of critical application data without authentication.

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-2026-91462 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91462 being exploited in the wild.

**How severe is CVE-2026-91462?** Medium severity, with a CVSS score of 5.9, 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, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.

**Is there a fix for CVE-2026-91462?** 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-2026-91462 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-91462?** 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

A difficult-to-exploit integrity vulnerability exists in the JGSS component of Oracle Java SE, affecting authentication and security operations. The vulnerability requires network access and can be exploited by supplying malicious data to JGSS APIs in applications or web services, bypassing normal authentication; it does not affect Java Web Start or applet execution. Successful exploitation allows an unauthenticated attacker to create, delete, or modify critical data accessible to Java SE instances.

## Affected products

- Oracle Java SE 8u503, 8u503-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27
- 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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