CVE-2026-56139
Received Received - Intake

Information Disclosure in Apache Camel Undertow

Publication date: 2026-07-06

Last updated on: 2026-07-06

Assigner: Apache Software Foundation

Description
Generation of Error Message Containing Sensitive Information vulnerability in Apache Camel Undertow Component. The camel-undertow HTTP server consumer exposes a muteException option that controls what is returned to the client when a route processing error occurs. This option defaulted to false, whereas the other Camel HTTP server components (camel-http / camel-jetty / camel-servlet and camel-platform-http) default it to true. With muteException=false, when a request triggers an exception during route processing the consumer writes the full Throwable stack trace into the HTTP response body as text/plain instead of returning an empty body. Any unauthenticated client that can reach the endpoint and cause a processing error - for example by sending a malformed request body, an invalid parameter, or otherwise triggering a route-internal failure - therefore receives a complete Java stack trace. Such a stack trace can disclose sensitive internal information, including credentials embedded in exception messages, internal host names and IP addresses, filesystem paths, dependency and version details, database and class names, and the application's internal structure, which an attacker can use to plan further attacks. In addition, for Rest DSL consumers the muteException option was not honoured at all: the RestUndertowHttpBinding was created with a hard-coded false, so the stack trace was returned even when muteException=true had been configured. This issue affects Apache Camel: from 4.0.0 before 4.14.8, from 4.15.0 before 4.18.3, from 4.19.0 before 4.21.0. Users are recommended to upgrade to version 4.21.0, which fixes the issue. If users are on the 4.14.x LTS releases stream, then they are suggested to upgrade to 4.14.8. If users are on the 4.18.x releases stream, then they are suggested to upgrade to 4.18.3. For deployments that cannot upgrade immediately, set muteException=true explicitly on the camel-undertow consumer (for example undertow: http://0.0.0.0:8080/api?muteException=true , or globally via the camel.component.undertow.mute-exception=true property), so that processing errors no longer return the stack trace to the client; note that on affected releases this workaround does not cover Rest DSL consumers, whose binding ignores the option until the fix is applied.

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Meta Information

Published
2026-07-06
Last Modified
2026-07-06
Generated
2026-07-06
AI Q&A
2026-07-06
EPSS Evaluated
N/A
NVD
CVE-2026-56139
EUVD
EUVD-2026-41851

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
apache camel 4.0.0
apache camel to 4.14.8 (inc)
apache camel 4.15.0
apache camel to 4.18.3 (inc)
apache camel 4.19.0
apache camel to 4.21.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-209 The product generates an error message that includes sensitive information about its environment, users, or associated data.

Attack-Flow Graph

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Executive Summary

This vulnerability exists in the Apache Camel camel-undertow HTTP server component. It involves the muteException option, which controls whether detailed error information is returned to clients when a processing error occurs during a route. By default, muteException was set to false in camel-undertow, unlike other Camel HTTP components where it defaults to true. This means that when an error happens, the full Java stack trace is sent back to the client instead of an empty response.

Because the stack trace can contain sensitive internal information such as credentials, hostnames, IP addresses, filesystem paths, dependency versions, database and class names, and application structure, exposing it to unauthenticated clients can help attackers plan further attacks.

Additionally, the Rest DSL consumer in camel-undertow ignored the muteException setting entirely due to a hard-coded false value, causing stack traces to be returned even if muteException was set to true.

Impact Analysis

This vulnerability can impact you by exposing sensitive internal information to any unauthenticated client that can reach the affected endpoint and trigger a processing error. Such information includes credentials, internal hostnames and IP addresses, filesystem paths, dependency and version details, database and class names, and the internal structure of the application.

Attackers can use this exposed information to better understand the system and plan more targeted and effective attacks against your infrastructure or application.

Detection Guidance

This vulnerability can be detected by sending requests to the camel-undertow HTTP server consumer endpoints that trigger processing errors, such as malformed request bodies or invalid parameters.

If the server responds with a full Java stack trace in the HTTP response body (text/plain), it indicates that the muteException option is set to false or not properly configured, exposing sensitive internal information.

A simple detection command using curl could be:

  • curl -v -X POST http://your-server/api -d 'malformed_data'

If the response contains a detailed Java stack trace, the vulnerability is present.

Mitigation Strategies

The recommended immediate mitigation is to upgrade Apache Camel to a fixed version: 4.14.8, 4.18.3, or 4.21.0 depending on your release stream.

If upgrading immediately is not possible, explicitly set the muteException option to true on the camel-undertow consumer to prevent stack traces from being returned in HTTP responses.

  • Configure the endpoint URI like: undertow:http://0.0.0.0:8080/api?muteException=true
  • Or set the global property: camel.component.undertow.mute-exception=true

Note that this workaround does not cover Rest DSL consumers, which ignore the muteException setting until the fix is applied.

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