CVE-2026-48203: Apache Camel: Camel-Solr: The SolrParam. and SolrField. Exchange header prefixes used non-Camel-prefixed names that bypass the HTTP header filter, allowing an HTTP client to inject Solr query parameters (server-side request forgery) and document fields

[Andrea Cosentino <acosentino () apache org>]

Severity: moderate 

Affected versions:

- Apache Camel (org.apache.camel:camel-solr) 4.0.0 before 4.14.8
- Apache Camel (org.apache.camel:camel-solr) 4.15.0 before 4.18.3
- Apache Camel (org.apache.camel:camel-solr) 4.19.0 before 4.21.0

Description:

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), Improper Input 
Validation, Server-Side Request Forgery (SSRF) vulnerability in Apache Camel Solr component.

The camel-solr producer copies Exchange message headers whose names begin with the SolrParam. prefix into the 
parameters of the Solr request, and headers whose names begin with the SolrField. prefix into the fields of the indexed 
Solr document. The prefix constants (SolrConstants.HEADER_PARAM_PREFIX / HEADER_FIELD_PREFIX) were the plain strings 
SolrParam. / SolrField.. Because these names do not start with the Camel / camel prefix, HttpHeaderFilterStrategy - 
which blocks only the Camel header namespace on the HTTP boundary - let them pass from an inbound HTTP request straight 
into the Exchange. In a route that bridges an HTTP consumer (for example platform-http) into a solr: producer, any HTTP 
client could therefore set SolrParam.* headers to inject arbitrary Solr request parameters - including shards or 
stream.url, which cause the Solr server to issue server-side requests to an attacker-chosen URL (server-side request 
forgery, for example to an internal service or a cloud metadata endpoint), or qt to reach administrative request 
handlers - and set SolrField.* headers to inject arbitrary fields into indexed documents. No credentials are required 
when the bridging consumer is unauthenticated.
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. After upgrading, routes that set Solr parameters or fields via the raw header prefixes 
must use CamelSolrParam. / CamelSolrField. instead of SolrParam. / SolrField.. For deployments that cannot upgrade 
immediately, strip the SolrParam.* and SolrField.* headers from any untrusted ingress before the solr: producer, and 
set the required Solr parameters and fields from a trusted source in the route.

Credit:

Yu Bao from Paypal (finder)
Andrea Cosentino (remediation developer)

References:

http://camel.apache.org/security/CVE-2026-48203.html
https://camel.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-48203