---
id: "CVE-2026-83400"
kind: "vulnerability"
aliases: ["CVE-2026-83400"]
title: "Oracle Java SE JAXP: unauthenticated network attacker causes partial denial of service"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["graalvm", "java", "oracle-jdk", "runtime", "web-services", "xml"]
not_affected_if: ["no-untrusted-input-to-jaxp"]
published_at: "2026-10-20T22:19:56+00:00"
first_seen_at: "2026-10-23T21:57:25+00:00"
updated_at: "2026-10-25T04:23:02+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83400", "first_seen_at": "2026-10-23T21:57:25+00:00"}]
---

# Oracle Java SE JAXP: unauthenticated network attacker causes partial denial of service

A flaw in the JAXP XML component of Oracle Java SE and GraalVM lets an unauthenticated remote attacker trigger a partial denial of service through services that pass data to those APIs. The advisory describes availability impact only, with no confidentiality or integrity loss.

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

## How to check

- Run `java -version` and compare the output with the affected versions listed in the advisory: Java SE 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1 and 27, GraalVM for JDK 17.0.20.1 and 21.0.12.1, GraalVM Enterprise 21.3.19.1.1.
- Check whether any internet-facing service parses untrusted XML through JAXP.

## Fix

- Update Oracle Java SE to a patched release from Oracle's Critical Patch Update for the affected line (exact fixed build numbers: unknown in the sources).
- Update Oracle GraalVM for JDK and GraalVM Enterprise to a patched release (exact fixed build numbers: unknown in the sources).

## Timeline

- 2026-10-23T21:57:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-83400

## From the sources

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JAXP).  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 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 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_