Quick answers
- Is CVE-2026-91451 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-91451 being exploited in the wild.
- How severe is CVE-2026-91451?
- Medium severity, with a CVSS score of 5.3, 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, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1.
- Is there a fix for CVE-2026-91451?
- 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-2026-91451 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-91451?
- 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
An easily exploitable integrity vulnerability exists in Oracle Java SE's Networking component, accessible via network protocols without authentication or user interaction. An unauthenticated attacker can supply malicious data to APIs to achieve unauthorized modification of accessible data. The vulnerability is restricted to direct API usage and does not affect Java Web Start or applet contexts.
Affected products
- Oracle Java SE 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1
- 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