---
id: "CVE-2026-73117"
kind: "vulnerability"
aliases: ["CVE-2026-73117"]
title: "Apache Juneau: unchecked response headers let attackers inject headers and redirects"
severity: "critical"
cvss: 10.0
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["apache-juneau", "java", "package", "rest-server"]
not_affected_if: ["no-request-data-in-headers", "no-request-data-in-redirects"]
published_at: "2026-11-05T12:17:51+00:00"
first_seen_at: "2026-11-05T12:38:48+00:00"
updated_at: "2026-11-05T12:40:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73117", "first_seen_at": "2026-11-05T12:38:48+00:00"}]
exploit_sources: []
---

# Apache Juneau: unchecked response headers let attackers inject headers and redirects

Apache Juneau's REST server passed response header values and redirect targets through without checking for CR/LF characters. An attacker can inject extra HTTP header lines or redirect users to an arbitrary external site when application code sets these values from request data.

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

## How to check

- Check the Juneau version in the build file, e.g. `mvn dependency:tree | grep juneau`, and confirm whether it is `9.2.0` or earlier
- Search application code for calls that set response headers or call `sendRedirect()` using request parameters
- Confirm whether the servlet container rejects CR/LF in headers (unknown from sources)

## Fix

- Apache Juneau: upgrade to `9.2.1`
- Applications that build redirect targets from request data: switch from `sendRedirect()` to `sendSafeRedirect()`

## Timeline

- 2026-11-05T12:38:48+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-73117

## From the sources

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability in Apache Juneau.

The Apache Juneau REST server passed response header values and redirect targets to the servlet container unchecked. An application that sets a response header or redirect target from request data could let a remote client inject header lines (where the servlet container does not itself reject CR/LF) or redirect users to an arbitrary external site. The framework itself does not build headers or redirects from request data; exposure depends on application code.

This issue affects Apache Juneau: through 9.2.0.

Users are recommended to upgrade to version 9.2.1, which fixes the issue. Header values are now sanitized by default; applications that build redirect targets from request data must also switch from sendRedirect() to the new sendSafeRedirect().

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