# CVE-2026-91418: Oracle Java SE denial of service in ImageIO

Source: https://junglewise.ai/threats/cve-2026-91418-vulnerability-in-the-oracle-java-se-oracle-javafx-oracle-graalvm  
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-2026-91418 · Severity: medium · CVSS 5.3 · Published 2026-10-20

Oracle Java SE and related Java products contain a vulnerability in image processing (ImageIO component) that allows an attacker to cause a partial service outage. An unauthenticated attacker can exploit this remotely by sending specially crafted image data through Java applications or web services, resulting in degraded performance or temporary unavailability of the affected Java application.

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), [Oracle JavaFX](https://junglewise.ai/threats/technologies/javafx). Vendors: [Oracle](https://junglewise.ai/threats/vendors/oracle).

## Quick answers

**Is CVE-2026-91418 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91418 being exploited in the wild.

**How severe is CVE-2026-91418?** 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, 27; Oracle JavaFX 21.0.12, 25.0.4, 27.

**Is there a fix for CVE-2026-91418?** 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-2026-91418 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-91418?** Check whether you run Oracle GraalVM Enterprise Edition, Oracle Graalvm For Jdk, Oracle Java SE or one of the others listed 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 ImageIO component of Oracle Java SE and related products, exploitable via multiple network protocols without authentication or user interaction. An attacker can supply malformed image data to APIs in the ImageIO component to trigger a partial denial of service condition. The vulnerability affects Java deployments including Java Web Start applications and applets that load untrusted code.

## Affected products

- Oracle Java SE 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27
- Oracle JavaFX 21.0.12, 25.0.4, 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
- 2026-10-20: advisory

## References

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

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