---
id: "CVE-2026-73101"
kind: "vulnerability"
aliases: ["CVE-2026-73101"]
title: "Apache Juneau: REST error responses leak internal exception details to clients"
severity: "critical"
cvss: 10.0
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["apache-juneau", "java", "package", "rest"]
not_affected_if: ["not-using-juneau-rest-server"]
published_at: "2026-11-05T12:17:51+00:00"
first_seen_at: "2026-11-05T12:38:47+00:00"
updated_at: "2026-11-05T12:40:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73101", "first_seen_at": "2026-11-05T12:38:47+00:00"}]
exploit_sources: []
---

# Apache Juneau: REST error responses leak internal exception details to clients

Apache Juneau's REST server sends the internal exception class and message in a "Thrown" response header and sometimes in the error body, even when stack traces are disabled. An attacker who sends requests that trigger errors learns implementation details about the server.

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

## How to check

- Check the Apache Juneau version in the project's build file (for example `pom.xml` or `build.gradle`) against the affected range.
- Send a request that triggers an error and look for a "Thrown" response header.

## Fix

- Apache Juneau: upgrade to `9.2.1`.

## Timeline

- 2026-11-05T12:38:47+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-73101

## From the sources

Generation of Error Message Containing Sensitive Information vulnerability in Apache Juneau.

The REST server sends the internal exception class and message to clients in a "Thrown" response header on every error response, and can include internal exception messages in the error body, even when stack-trace rendering is disabled. This reveals implementation details to remote clients.

This issue affects Apache Juneau: through 9.2.0.

Users are recommended to upgrade to version 9.2.1, which fixes the issue.

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