CVE-2026-56139 camel vulnerability
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.
Quick answer
apache camel should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Review vendor advisory for affected versions.
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Apache Camel is affected by CVE-2026-56139, a credential exposure risk. Generation of Error Message Containing Sensitive Information vulnerability in Apache Camel Undertow Component. The recommended remediation is to update to Apache Camel 4.14.8, 4.18.3, 4.21.0, or a later fixed release for the deployed Undertow component branch. Until the update is complete, set muteException=true and avoid returning stack traces from camel-undertow routes until patched, review logs, and reduce exposure of the affected package, route, provider, or service workflow.
- Inventory every deployment, package, dependency, build runner, integration, route, service, and managed environment that uses Apache Camel.
- Confirm the installed version/build and compare it with versions from 4.19.0 before 4.21.0. Users are recommended through upgrade and the source advisory for CVE-2026-56139.
- Apply the vendor-supported fix: update to Apache Camel 4.14.8, 4.18.3, 4.21.0, or a later fixed release for the deployed Undertow component branch.
- If the update cannot be applied immediately, set muteException=true and avoid returning stack traces from camel-undertow routes until patched; disable unnecessary public access, package-install paths, file processing, webhooks, message consumers, or high-risk integrations until patched.
- Review application, CI/CD, package manager, container, reverse-proxy, WAF, authentication, route, and audit logs for activity related to CVE-2026-56139.
- Rotate sessions, API tokens, package registry credentials, cloud credentials, webhook secrets, service credentials, and administrator passwords if logs or affected data indicate compromise, credential exposure, or unauthorized access.
- Clear caches, restart affected services, rebuild affected containers or build agents when appropriate, and remove temporary files, malicious artifacts, stored payloads, or unsafe configuration created during exploitation attempts.
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Verify the fix
- Confirm Apache Camel now reports Apache Camel 4.14.8, 4.18.3, 4.21.0, or a later fixed release for the deployed Undertow component branch or a later vendor-supported fixed release/build for the deployed branch.
- Verify the affected workflow no longer allows the behavior described in CVE-2026-56139, using a safe regression test, dependency inventory, or vendor validation method.
- Review logs after remediation for continued exploit attempts, denial-of-service symptoms, suspicious redirects, unauthorized requests, path traversal, header manipulation, credential exposure, or configuration changes.
- Rerun a Fixnx scan and any product-specific scanner, package audit, dependency check, route regression test, or integration test relevant to the affected service.
- Document affected assets, fixed versions, mitigation decisions, validation evidence, and any cleanup, rebuild, or credential rotation performed.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-56139?
apache camel should be checked against the vendor advisory and trusted references linked on this page.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.