---
id: "CVE-2026-83395"
kind: "vulnerability"
aliases: ["CVE-2026-83395"]
title: "Oracle Java SE: Networking flaw lets unauthenticated attackers alter data and disrupt service"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["graalvm", "java", "jvm", "runtime", "self-hosted"]
not_affected_if: ["no-network-facing-java", "not-listed-versions"]
published_at: "2026-10-20T22:19:55+00:00"
first_seen_at: "2026-10-23T21:57:25+00:00"
updated_at: "2026-10-25T03:51:32+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83395", "first_seen_at": "2026-10-23T21:57:25+00:00"}]
---

# Oracle Java SE: Networking flaw lets unauthenticated attackers alter data and disrupt service

A flaw in the Networking component of Oracle Java SE and GraalVM lets a remote, unauthenticated attacker over the network modify or delete some accessible data and partly disrupt the service. It is exploitable through APIs fed by web services, and also affects sandboxed Java applets and Web Start applications 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 against the affected releases: 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.
- For GraalVM, check `native-image --version` against 17.0.20.1, 21.0.12.1 and 21.3.19.1.1.
- Look for sandboxed applets or Java Web Start use on client machines.

## Fix

- Oracle Java SE: update to a release newer than the affected builds listed above (the sources do not name the exact patched build).
- Oracle GraalVM for JDK and GraalVM Enterprise Edition: update to a patched release from Oracle's April 2026 Critical Patch Update.
- Rebuild and redeploy services that bundle a JRE.

## Timeline

- 2026-10-23T21:57:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-83395

## From the sources

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Networking).  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 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 GraalVM for JDK, Oracle GraalVM Enterprise Edition.  Successful attacks of this vulnerability can result in  unauthorized update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE, 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 6.5 (Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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_