CVE-2026-63621

CVE-2026-63621 is a medium-severity vulnerability in Apache Camel with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

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.

Frequently asked questions

What is CVE-2026-63621?
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.
How severe is CVE-2026-63621?
CVE-2026-63621 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-63621 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-63621?
CVE-2026-63621 affects Apache Camel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-63621?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-63621 published?
CVE-2026-63621 was published on 2026-08-24 and last updated on 2026-08-27.

References

Affected products (1)

More vulnerabilities in Apache Camel

All CVEs affecting Apache Camel →

Other CWE-20 (Improper Input Validation) vulnerabilities

Browse all CWE-20 (Improper Input Validation) vulnerabilities →