Apache Camel Security Advisory - CVE-2026-66906

Apache Camel security advisory: CVE-2026-66906

Severity

MEDIUM

Summary

Camel-Azure-Storage-Blob: the downloadBlobToFile operation built the local download target from the remote blob name without constraining it to the configured fileDir, so a name containing traversal segments could write outside that directory

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-azure-storage-blob component can download an Azure Storage blob to the local filesystem through its downloadBlobToFile operation, writing into the directory named by the fileDir endpoint option, which is documented as usable from both the producer and the consumer. BlobOperations.downloadBlobToFile built the local target by joining fileDir with the remote blob name exactly as the Azure SDK reported it (new File(fileDir, client.getBlobName())) and passed the result straight to the SDK download call, with no lexical normalization and no check that the resolved location stayed inside fileDir. The blob name is not route-controlled data: the consumer enumerates the container in BlobConsumer.createBatchExchangesFromContainer, which lists blobs and creates one exchange per entry from BlobItem.getName() verbatim, applying no name filtering by default. A blob name containing parent-directory segments therefore resolved to a location outside the configured fileDir, letting anyone able to influence the names present in the consumed container cause Camel to create or overwrite a file at a location of their choosing, with the privileges of the Camel process. Depending on what the process can write to, overwriting a file outside the download directory can escalate beyond the loss of integrity of that file. Azure Storage blob containers use a flat namespace in which the blob name is an opaque key, so a name carrying such segments is stored and listed as given. The fileDir option is an ordinary common-group configuration parameter and carries no security marker, so nothing signalled to users that its value was not being enforced as a containment boundary. Camel's other file-download consumers - camel-file, camel-ftp, camel-smb, camel-mina-sftp and camel-azure-files - already constrained their local downloads to the configured directory using a path-segment boundary check; the camel-azure-storage-blob download path was not covered by that work.

Notes

The JIRA ticket: https://issues.apache.org/jira/browse/CAMEL-23942 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/24542 (commit 55fcbaf8bc1936cae90abdea5adecbc43e57340e) and backported to camel-4.18.x in https://github.com/apache/camel/pull/24581 (commit 007929bb732a8c5e3e49d4d3c6c8adc2aab13340) and to camel-4.14.x in https://github.com/apache/camel/pull/24582 (commit 857d0cd3024b706ce80f3d2a4aa111e5e94a3e59). A follow-up documentation change, https://github.com/apache/camel/pull/24585 (commit 513d0e18a4b54220f6c12ab84d3bea9641f9776d), synchronised the upgrade-guide note for the maintenance branches onto main.

The fix resolves the remote blob name against fileDir, normalizes the result lexically so that parent-directory segments are collapsed, and then verifies that the normalized target is still contained within the normalized fileDir on path-segment boundaries - so a sibling directory whose name merely extends fileDir as a string prefix is not treated as contained. A name that resolves outside the directory is rejected with an IllegalArgumentException before the Azure SDK download call is invoked. On main the check lives in a shared helper, AzureFileNameHelper.resolveWithinDirectory, added to camel-azure-common; because that module was introduced in 4.19.0 and does not exist on the maintenance branches, the 4.18.4 and 4.14.9 releases carry the identical logic replicated as a private method inside BlobOperations. The check is implemented with java.nio.file only and introduces no new dependency. The issue is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and belongs to the same family as the local-download containment work tracked in CAMEL-23765 and CAMEL-23868, which covered the generic and remote file consumers. The equivalent defect in the camel-azure-storage-datalake consumer is addressed separately in CVE-2026-60093, and the two advisories share the same fix (CAMEL-23942).

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, constrain the names the consumer will act on using the regex endpoint option, which is applied to each listed blob name as a full-string match, so that only simple single-segment names are accepted and any name carrying a path separator or a parent-directory segment is filtered out before an exchange is created; the prefix option can additionally narrow the listing server-side, noting that when both are set regex takes priority and prefix is ignored. Alternatively, avoid the downloadBlobToFile operation on untrusted containers and write the payload from the route under a file name the route itself controls, rather than one taken from the remote listing. As defence in depth, treat the blob names in any externally writable container as untrusted input and do not derive local filesystem paths from them.

Credit

Reported by n0mi1k and Hiep Nguyen

References

PGP signed advisory data: CVE-2026-66906.txt.asc
Mitre CVE Entry: https://www.cve.org/CVERecord?id=CVE-2026-66906