Apache Camel Security Advisory - CVE-2026-71300

Apache Camel security advisory: CVE-2026-71300

Severity

MEDIUM

Summary

Camel-Atmosphere-Websocket: WebSocket dispatch header injection - the producer selected its target peers through Exchange headers whose names sat outside the filtered Camel namespace, so an external sender could take over the dispatch decision

Versions affected

From 4.0.0 before 4.14.9, from 4.15.0 before 4.18.4, from 4.19.0 before 4.22.0.

Versions fixed

4.14.9, 4.18.4 and 4.22.0

Description

The camel-atmosphere-websocket producer selects which connected WebSocket peers a message is delivered to through Exchange headers, and the string values of those headers sat outside the Camel namespace: websocket.connectionKey and websocket.connectionKey.list, along with websocket.sendToAll, websocket.eventType and websocket.errorType. WebsocketEndpoint extends ServletEndpoint and so inherits HttpHeaderFilterStrategy, which filters only the Camel and camel prefixes; the dotted names therefore fell outside the filtered namespace and were admitted in both directions by every HTTP-family consumer. In a route bridging an HTTP consumer into an atmosphere-websocket producer, an external sender could supply the list header and take over the producer's dispatch decision. WebsocketProducer.process tests the list header before the single-key header, so an injected value discarded the recipient the route had selected: a notification intended for one connected client could be suppressed, or delivered instead to a different client whose connection key the sender knows. The header need not be a query parameter and need not be supplied as a list literally - Camel's HTTP binding promotes a repeated header name, and a bracketed value, to a List when mapping onto the Exchange - so an ordinary inbound HTTP header is sufficient to reach the list-valued branch. This is distinct from CVE-2026-55993, which concerns the consumer-side query-parameter path in the same component. The behaviour dates back to the introduction of these constants, first released in 2.17.0, and was unchanged until this fix.

Notes

The JIRA ticket: https://issues.apache.org/jira/browse/CAMEL-24359 refers to the various commits that resolved the issue, and has more details.

The fix was merged on main in https://github.com/apache/camel/pull/25366 (commit 60ca704c0379e6e87107158c0b2174c3f0f2f48a) and backported to camel-4.18.x in https://github.com/apache/camel/pull/25382 (commit 66567833fb1efe6d66c6618dbb48295cce4c84ba) and to camel-4.14.x in https://github.com/apache/camel/pull/25383 (commit 49e197a66158eb7151b461b46b37407df2e13591). A follow-up documentation change, https://github.com/apache/camel/pull/25384 (commit b6532db34afe185d85fd14daf27f2a460018b078), synchronised the upgrade-guide entries for the maintenance branches onto main.

The fix renames the five Exchange header string values from the legacy dotted websocket. prefix to the project-wide convention documented in design/headers.adoc, so that websocket.connectionKey becomes CamelAtmosphereWebsocketConnectionKey and the remaining four follow the same form. The Java field names in WebsocketConstants are unchanged, so code referring to the constants symbolically continues to work; only code using the literal strings must be updated. The remedy is a rename rather than an added filter because the producer reads these values with in.getHeader, which does not consult a HeaderFilterStrategy at all - moving the names into the Camel namespace is what allows the upstream consumer’s own default filter to block them at its boundary, before they ever reach the producer. An earlier pass over this component applied the inherited filter strategy to the consumer’s WebSocket query parameters but neither renamed the constants nor gave the component a dedicated strategy, which is why this path remained open. The issue is classified as CWE-20 (Improper Input Validation) and belongs to the same header-injection family as the Camel consumer advisories published previously.

Mitigation

Users are recommended to upgrade to version 4.22.0, which fixes the issue. If users are on the 4.14.x LTS releases stream, then they are suggested to upgrade to 4.14.9. If users are on the 4.18.x releases stream, then they are suggested to upgrade to 4.18.4. For deployments that cannot upgrade immediately, strip the dispatch headers at the trust boundary before the producer, for example with removeHeaders(“websocket.*”) placed between the HTTP consumer and the atmosphere-websocket producer. Note that the fix renames the header string values into the Camel namespace, which is a breaking change for routes that set them by literal string: routes referencing the WebsocketConstants fields symbolically are unaffected, and the change is documented in the upgrade guides. As defence in depth, do not bridge an untrusted HTTP consumer directly into a WebSocket producer whose dispatch is header-driven without stripping the dispatch namespace first.

Credit

This issue was discovered by Barak Srour from Apiiro

References

PGP signed advisory data: CVE-2026-71300.txt.asc
Mitre CVE Entry: https://www.cve.org/CVERecord?id=CVE-2026-71300