---
id: "CVE-2026-83380"
kind: "vulnerability"
aliases: ["CVE-2026-83380"]
title: "Oracle Java SE: JAAS component flaw leaks a subset of data"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["graalvm", "java", "oracle-jdk", "runtime", "self-hosted", "web-services"]
not_affected_if: ["default-config"]
published_at: "2026-10-20T22:19:54+00:00"
first_seen_at: "2026-10-23T21:57:25+00:00"
updated_at: "2026-10-25T04:23:03+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83380", "first_seen_at": "2026-10-23T21:57:25+00:00"}]
---

# Oracle Java SE: JAAS component flaw leaks a subset of data

A flaw in the JAAS component of Oracle Java SE, Oracle GraalVM for JDK and GraalVM Enterprise Edition lets an unauthenticated network attacker read a subset of accessible data. The attack works through APIs in that component, for example via a web service that passes data into them.

_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 listed in the advisory: Java SE 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.
- For GraalVM, check the installed JDK version against GraalVM for JDK 17.0.20.1 and 21.0.12.1, or GraalVM Enterprise Edition 21.3.19.1.1.
- Check whether any service exposes JAAS-backed APIs to untrusted network input.

## Fix

- Update Oracle Java SE to a patched release from Oracle's April 2026 Critical Patch Update (the sources do not give the exact fixed build numbers).
- Update Oracle GraalVM for JDK and GraalVM Enterprise Edition to the patched releases named in Oracle's advisory.
- Redeploy services built on the patched runtime.

## Timeline

- 2026-10-23T21:57:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-83380

## From the sources

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JAAS).  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 read access to a subset of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data. 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 (Confidentiality impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

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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_