Is CVE-2026-91375 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-91375 being exploited in the wild.

How severe is CVE-2026-91375?

Medium severity, with a CVSS score of 4.7, 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-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.

Is there a fix for CVE-2026-91375?

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-2026-91375 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-91375?

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.

CVE-2026-91375: Oracle Java SE integrity violation in Libraries component

CVE-2026-91375 · Severity: medium · CVSS 4.7 · Published 2026-10-20

Oracle Java SE contains a flaw in its Libraries component that allows a local attacker to modify critical data without authentication, provided they can trick a user into interacting with malicious input. This affects both standalone Java applications and sandboxed Java Web Start/applet deployments that load untrusted code from the internet. Successful exploitation results in unauthorized modification of sensitive data accessible to Java applications.

Technologies: Oracle GraalVM Enterprise Edition, Oracle Graalvm For Jdk, Oracle Java SE. Vendors: Oracle.

Quick answers

Is CVE-2026-91375 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-91375 being exploited in the wild.
How severe is CVE-2026-91375?: Medium severity, with a CVSS score of 4.7, 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-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.
Is there a fix for CVE-2026-91375?: 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-2026-91375 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-91375?: 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 Oracle Java SE's Libraries component, requiring local access to the infrastructure and user interaction with untrusted data. The vulnerability is exploitable via APIs in the affected component, including through web services that supply data to those APIs, or through sandboxed Java Web Start applications and applets loading untrusted code. An unauthenticated attacker can achieve unauthorized creation, deletion, or modification of critical data or all Oracle Java SE accessible data.

Affected products

Oracle Java SE 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

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