CVE-2026-33453: Apache Camel Camel-Coap RCE Vulnerability

CVE-2026-33453 Overview

CVE-2026-33453 is a critical remote code execution vulnerability in the Apache Camel Camel-CoAP component. The vulnerability stems from improper handling of CoAP request URI query parameters, which are mapped directly into Camel Exchange message headers without any filtering through a HeaderFilterStrategy. This allows unauthenticated attackers to inject arbitrary Camel internal headers into the Exchange, potentially leading to arbitrary OS command execution when routes forward requests to header-sensitive producers.

Critical Impact
Unauthenticated remote code execution via a single UDP packet to the CoAP port (default 5683), with interactive command execution capabilities and no authentication required.

Affected Products

Apache Camel versions 4.14.0 through 4.14.5
Apache Camel version 4.18.0 before 4.18.1
Apache Camel version 4.19.0

Discovery Timeline

April 27, 2026 - CVE-2026-33453 published to NVD
April 28, 2026 - Last updated in NVD database

Technical Details for CVE-2026-33453

Vulnerability Analysis

The vulnerability exists in the CamelCoapResource.handleRequest() method, which iterates over OptionSet.getUriQuery() and calls camelExchange.getIn().setHeader(...) for every query parameter without applying any header filtering. The CoAPEndpoint class extends DefaultEndpoint rather than DefaultHeaderFilterStrategyEndpoint, and CoAPComponent does not implement HeaderFilterStrategyComponent. This architectural oversight means the component contains no references to HeaderFilterStrategy whatsoever, leaving incoming CoAP requests completely unfiltered.

When a malicious CoAP request reaches a Camel route, the attacker-controlled query parameters are converted directly into Camel message headers. If the route delivers the message to header-sensitive producers such as camel-exec, camel-sql, camel-bean, camel-file, or template components (camel-freemarker, camel-velocity), these injected headers can alter producer behavior. In the case of camel-exec, the CamelExecCommandExecutable and CamelExecCommandArgs headers override the endpoint's configured executable and arguments, resulting in arbitrary OS command execution under the privileges of the Camel process.

The producer's output is written back to the Exchange body and returned in the CoAP response payload by CamelCoapResource, providing attackers with an interactive RCE channel without requiring out-of-band data exfiltration.

Root Cause

The root cause is the improper controlled modification of dynamically-determined object attributes (CWE-915). The camel-coap component fails to implement or utilize any HeaderFilterStrategy to sanitize incoming CoAP request parameters before they are mapped to Camel Exchange headers. This design flaw allows external input to directly influence internal Camel headers, including those prefixed with Camel* that control component behavior.

Attack Vector

Exploitation requires minimal prerequisites: a single unauthenticated UDP datagram sent to the CoAP port (default 5683). CoAP (RFC 7252) has no built-in authentication mechanism, and DTLS is optional and disabled by default. Because the protocol is UDP-based, traditional HTTP-layer WAF and IDS controls do not apply, making detection and prevention significantly more challenging.

An attacker crafts a CoAP request with malicious query parameters designed to inject Camel internal headers. When processed by a vulnerable route that forwards to camel-exec or similar header-sensitive producers, the injected headers override the configured command and arguments, achieving arbitrary command execution.

For detailed technical analysis and proof-of-concept information, refer to the Apache Camel CVE-2026-33453 Advisory and the OpenWall OSS-Security Mailing List Post.

Detection Methods for CVE-2026-33453

Indicators of Compromise

Unexpected CoAP traffic on port 5683/UDP from external or untrusted sources
CoAP requests containing query parameters with Camel* prefixed names (e.g., CamelExecCommandExecutable, CamelExecCommandArgs)
Unusual process spawning from Java/Camel application processes
Unexpected outbound network connections or data exfiltration from Camel service hosts

Detection Strategies

Monitor UDP traffic on port 5683 for CoAP requests containing suspicious query parameter names that match Camel internal header patterns
Implement application-level logging to capture all incoming CoAP requests and their parameters before processing
Deploy endpoint detection and response (EDR) solutions to identify anomalous child processes spawned by the Camel application
Use network segmentation to restrict CoAP service accessibility to trusted networks only

Monitoring Recommendations

Enable verbose logging in Apache Camel to capture Exchange header modifications and producer invocations
Set up alerts for any CoAP requests containing Camel* prefixed query parameters
Monitor for unexpected system command execution patterns from the Camel process user context
Implement DTLS on CoAP endpoints to enforce authenticated connections and enable encrypted traffic analysis

How to Mitigate CVE-2026-33453

Immediate Actions Required

Upgrade Apache Camel to version 4.18.1 or later, or version 4.19.0 which addresses this vulnerability
If immediate patching is not possible, disable or restrict access to the camel-coap component
Implement network-level access controls to restrict CoAP port (5683/UDP) access to trusted sources only
Enable DTLS on CoAP endpoints to require authenticated connections

Patch Information

Apache has released patched versions that address this vulnerability. Users running affected versions should upgrade to Apache Camel version 4.18.1 or 4.19.0. The fix implements proper header filtering through HeaderFilterStrategy to prevent untrusted CoAP query parameters from being mapped to sensitive internal Camel headers. For detailed patch information, see the Apache Camel CVE-2026-33453 Advisory.

Workarounds

Implement firewall rules to block external access to CoAP ports (5683/UDP) until patching is complete
Deploy a custom HeaderFilterStrategy implementation to filter out Camel* prefixed headers from incoming requests
Remove or disable the camel-coap component from routes if CoAP functionality is not required
Configure network segmentation to isolate CoAP-enabled services from untrusted networks

bash

# Example: Block external CoAP traffic using iptables
iptables -A INPUT -p udp --dport 5683 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p udp --dport 5683 -j DROP