CVE-2026-63621 Apache Camel-Knative: CloudEvent extension fields received in structured content mode were mapped onto message headers without applying any header filter strategy

What is CVE-2026-63621?

CVE-2026-63621 is a medium-severity server-side request forgery vulnerability in Apache Camel, published on 24 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Improper Input Validation, Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') vulnerability in Apache Camel Knative component

The Knative consumer in camel-knative maps inbound CloudEvent attributes onto Camel message headers. In binary content mode the HTTP-header path filters Camel-internal headers through KnativeHttpHeaderFilterStrategy, but in structured content mode (Content-Type application/cloudevents+json) the CloudEvent extension fields are read directly from the JSON body and every extension key is copied into the Exchange headers without applying any HeaderFilterStrategy (CloudEventProcessors, spec versions 1.0, 1.0.1 and 1.0.2). As a result, an unauthenticated attacker can inject Camel-internal headers (e.g. CamelHttpUri, CamelHttpPath, CamelFileName) via a structured-mode CloudEvent request, matched case-insensitively against Camel's header map. When a route forwards messages from a Knative consumer to a header-driven component such as camel-http or camel-file, the injected headers override configured values, enabling server-side request forgery (SSRF), path traversal or message-dispatch redirection depending on the route. This is an incomplete fix of the inbound header filtering previously added for the binary content-mode path, and is the same pattern addressed in camel-cxf/camel-knative (CVE-2026-47323), camel-undertow (CVE-2025-30177), the broader incoming-header filter (CVE-2025-27636 and CVE-2025-29891), and the non-HTTP strategies (CVE-2026-40453).

This issue affects Apache Camel: from 3.15.0 before 4.14.9, from 4.15.0 before 4.18.4, from 4.19.0 before 4.21.0.

Users are recommended to upgrade to version 4.22.0, which fixes the issue. If users are on the 4.18.x LTS releases stream, then they are suggested to upgrade to 4.18.4. If users are on the 4.14.x LTS releases stream, then they are suggested to upgrade to 4.14.9. The non-LTS releases 4.15.0 through 4.17.0 and 4.19.0 through 4.21.0 are affected but do not receive a maintenance fix; users on those versions should upgrade to 4.18.4 or 4.22.0.

Weakness: CWE-74, CWE-20

Which versions are affected by CVE-2026-63621?

6 open source packages ship an affected version, including org.apache.camel:camel-knative. It affects 1 product.

Products include Apache Camel.

How do I fix CVE-2026-63621?

Upgrade org.apache.camel:camel-knative to a fixed version for your release line: 4.14.9, 4.18.4 or 4.22.0.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-63621 being exploited?

There is no known exploitation of CVE-2026-63621 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Apache Camel

• CVE-2026-33453 Apache camel-coap allows header injection that can lead to remote code execution Critical 10.0
• CVE-2026-40453 Apache Camel has an incomplete fix for CVE-2025-27636 Critical 9.9
• CVE-2026-80351 Apache Camel K: Camel K Tenant repositories reach Maven execution inside operator pod Critical 9.8
• CVE-2026-80352 Apache Camel K: Camel K Master trait serviceAccountName YAML injection lets CR author apply arbitrary objects Critical 9.8
• CVE-2026-71300 Apache Camel: Camel-Atmosphere-Websocket: WebSocket dispatch header injection Critical 9.8

All Apache Camel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-vvwm-3j43-7pfm.