CVE-2026-40047: Apache Camel: Camel-Docling: Insufficient validation of custom CLI arguments enables argument injection and path traversal in DoclingProducer

[Andrea Cosentino <acosentino () apache org>]

Severity: moderate 

Affected versions:

- Apache Camel (org.apache.camel:camel-docling) 4.15.0 before 4.18.3

Description:

Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') vulnerability in Apache Camel 
Docling component.

The camel-docling component invokes the external `docling` command-line tool by assembling an argument list in 
DoclingProducer and executing it through java.lang.ProcessBuilder. Custom CLI arguments supplied through the 
`CamelDoclingCustomArguments` exchange header (a List<String>) were appended to that argument list with insufficient 
validation: the original implementation relied on a denylist of disallowed flags and only rejected path values that 
contained a literal `../` sequence. As a result, a Camel route that forwards externally-influenced data into the 
`CamelDoclingCustomArguments` header (or into the path-bearing headers used to build the invocation) could cause the 
producer to pass unrecognized or unintended `docling` CLI flags to the subprocess, and could supply path-like argument 
values that resolved outside the intended directory through traversal sequences not caught by the literal `../` check. 
Because Camel itself builds the `docling` invocation from these values, the component is responsible for constraining 
them, and the weak validation allowed CLI-argument injection and directory traversal in the arguments passed to the 
external tool. The invocation uses the list-based form of ProcessBuilder, so a shell does not interpret the argument 
values; OS command injection through shell metacharacters was not possible, and the metacharacter rejection added by 
the fix is defense-in-depth.
This issue affects Apache Camel: from 4.15.0 before 4.18.3.

Users are recommended to upgrade to a release that contains the CAMEL-23212 fix. On the mainline the fix is included 
from Apache Camel 4.19.0 (and later releases such as 4.20.0). For users on the 4.18.x LTS releases stream, upgrade to 
4.18.3. The fix replaces the denylist with a strict allowlist of recognized `docling` CLI flags (rejecting any 
unrecognized flag, and rejecting producer-managed flags such as the output-directory flags), defensively rejects shell 
metacharacters in argument values, and normalizes path-like values with Path.normalize() before validating them so that 
traversal sequences which bypass a literal `../` check are detected. As defence in depth, route authors should avoid 
mapping untrusted message content into the `CamelDoclingCustomArguments` header and the path-bearing headers, and 
should strip Camel-internal headers from messages that arrive from untrusted producers.

Credit:

Andrea Cosentino from Apache Software Foundation (finder)
Andrea Cosentino from Apache Software Foundation (remediation developer)

References:

https://camel.apache.org/security/CVE-2026-40047.html
https://camel.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-40047