---
id: "CVE-2026-91418"
kind: "vulnerability"
aliases: ["CVE-2026-91418"]
title: "Oracle Java SE: ImageIO flaw lets unauthenticated network attackers crash the JVM"
severity: "medium"
cvss: 5.3
epss: 0.00402
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["graalvm", "java", "javafx", "jvm", "oracle-java", "runtime", "server-side-java"]
not_affected_if: ["no-imageio-on-untrusted-input", "no-java-runtime-listed"]
published_at: "2026-10-20T22:20:45+00:00"
first_seen_at: "2026-10-23T21:57:26+00:00"
updated_at: "2026-10-25T12:38:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91418", "first_seen_at": "2026-10-23T21:57:26+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91418", "first_seen_at": "2026-10-25T12:38:52+00:00"}]
---

# Oracle Java SE: ImageIO flaw lets unauthenticated network attackers crash the JVM

A flaw in the ImageIO component of Oracle Java SE, JavaFX and GraalVM lets an unauthenticated attacker over the network cause a partial denial of service. The sources say it is reachable through web services that pass data to the affected APIs, and it also applies to sandboxed Java applets and Web Start apps that run untrusted code.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `java -version` and compare the build against the affected releases listed in the sources (for example `8u503`, `11.0.32.1`, `17.0.20.1`, `21.0.12.1`, `25.0.4.1`)
- Check whether any service imports `javax.imageio` or `java.desktop` image reading on data from untrusted sources
- unknown whether sandboxed applets or Web Start are in use beyond what the description says

## Fix

- Move Oracle Java SE to a patched release from the vendor's April 2026 Critical Patch Update, matching your major line (`8u503` or later for 8, `11.0.32.1` or later for 11, `17.0.20.1` or later for 17, `21.0.12.1` or later for 21, `25.0.4.1` or later for 25)
- Update JavaFX to `21.0.12`, `25.0.4` or `27`, and GraalVM for JDK to `17.0.20.1` or `21.0.12.1` where used
- unknown whether a specific fixed build number is required beyond these versions

## Timeline

- 2026-10-23T21:57:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91418
- 2026-10-25T12:38:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91418

## From the sources

Vulnerability in the Oracle Java SE, Oracle JavaFX, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: ImageIO).  Supported versions that are affected are Oracle Java SE: 8u503, 8u503-perf, 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 and  21.0.12.1; Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle JavaFX, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition.  Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE, Oracle JavaFX, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 5.3 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_