# CVE-2026-73101: Apache Juneau information disclosure in REST error responses

Source: https://junglewise.ai/threats/cve-2026-73101-generation-of-error-message-containing-sensitive-information  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-05  
License: CC BY 4.0 with a link back

CVE-2026-73101 · Severity: info · Published 2026-11-05

Apache Juneau is a REST framework library used to build web services. The REST server component leaks internal exception class names and messages to remote clients in error responses, revealing implementation details that could aid attackers in finding vulnerabilities even when stack traces are disabled.

Technologies: [Apache Juneau](https://junglewise.ai/threats/technologies/juneau). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-73101 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-73101 being exploited in the wild.

**How severe is CVE-2026-73101?** Informational severity, published 5 November 2026.

**Which products and versions are affected?** Apache Juneau through 9.2.0.

**Is there a fix for CVE-2026-73101?** Yes: fixed in 9.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-73101 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-73101?** Check whether you run Apache Juneau at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 9.2.1

## Technical details

The vulnerability is an information disclosure issue where Apache Juneau's REST server includes the internal exception class and message in the "Thrown" response header and error body on every error response, exposing implementation details to remote clients. This occurs even when stack-trace rendering is disabled, allowing unauthenticated remote attackers with network access to gather sensitive information through normal error handling.

## Affected products

- Apache Juneau through 9.2.0

## Timeline

- 2026-11-05: disclosed

## References

- [https://repo.maven.apache.org/maven2](https://repo.maven.apache.org/maven2)
- [https://lists.apache.org/thread.html/j05q7vw08j48o96tdlzcsd4sozx1lyl6](https://lists.apache.org/thread.html/j05q7vw08j48o96tdlzcsd4sozx1lyl6)

## Related threats

- [Apache Juneau cross-site scripting in HTML serialization](https://junglewise.ai/threats/cve-2026-96677-improper-neutralization-of-input-during-web-page-generation-cross)
- [Apache Juneau HTTP response splitting via unvalidated headers](https://junglewise.ai/threats/cve-2026-73117-improper-neutralization-of-crlf-sequences-in-http-headers-http)
- [Apache Juneau RestClient credential leakage on redirect](https://junglewise.ai/threats/cve-2026-73116-insufficiently-protected-credentials-vulnerability-in-apache)
- [Apache Juneau sensitive information insertion in log file](https://junglewise.ai/threats/cve-2026-73100-insertion-of-sensitive-information-into-log-file-vulnerability-in)
- [Apache Juneau CSRF vulnerability via content query parameter](https://junglewise.ai/threats/cve-2026-73099-cross-site-request-forgery-csrf-vulnerability-in-apache-juneau)