Apache Camel Security Advisory - CVE-2026-66907

Apache Camel security advisory: CVE-2026-66907

Severity

MEDIUM

Summary

Camel-Google-Storage: the consumer appended the remote object name to the configured downloadFileName directory without constraining the result, so an object 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-google-storage consumer downloads Google Cloud Storage objects to the local filesystem when the downloadFileName option is set. That option is documented as a folder or a filename, and when its value contains no expression token the consumer builds the local destination by appending the object name to it: evaluateFileExpression sets the Exchange file-name header to the remote object name and evaluates downloadFileName + "/${file:name}". The ${file:name} token returns the file-name header verbatim, unlike ${file:onlyname}, which applies FileUtil.stripPath to it. The resulting string was passed directly to new File(result) and blob.downloadTo(file.toPath()) with no lexical normalization and no check that the destination stayed inside the configured directory. The object name is not route-controlled data: the consumer lists the bucket, iterates every returned blob and creates one exchange per object from blob.getBlobId().getName() verbatim, and the filter option that could restrict those names is not applied at all unless it has been explicitly set. Google Cloud Storage object names are opaque UTF-8 keys that the service stores and lists exactly as written, with no server-side canonicalization, and a forward slash is only a display convention for pseudo-directories, so a key containing parent-directory segments survives round-tripping intact. An object name containing such segments therefore resolved to a location outside the configured downloadFileName directory, letting anyone able to influence the names present in the consumed bucket 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. The downloadFileName option is an ordinary consumer parameter and carries no security marker, so nothing signalled to users that its value was not being enforced as a containment boundary. The defect is consumer-only; the producer has no download-to-file sink. Camel's other file-download consumers - camel-file, camel-ftp, camel-smb, camel-mina-sftp, camel-azure-files and the Azure Storage download paths - already constrained their local downloads to the configured directory using a path-segment boundary check; camel-google-storage was the remaining object-store download sink not covered by that work.

Notes

The JIRA ticket: https://issues.apache.org/jira/browse/CAMEL-24279 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/25179 (commit a6f73c6d2828fe2b76bf423bad92f98d80af7437) and backported to camel-4.18.x in https://github.com/apache/camel/pull/25180 (commit 277ab7b7af9bd3beb789d458d54b00b704647191) and to camel-4.14.x in https://github.com/apache/camel/pull/25181 (commit 4b9b4ade15148e1512b39f302075b36c7a092e86). A follow-up documentation change, https://github.com/apache/camel/pull/25182 (commit 09d246d411cb2ba6bb1d7832e0c232056d955d34), synchronised the upgrade-guide note for the maintenance branches onto main.

The fix adds a package-private GoogleCloudStorageFileNameHelper.assertWithinDirectory, which normalizes both the configured download directory and the resolved destination lexically so that parent-directory segments are collapsed, and then verifies that the destination is still contained within the directory on path-segment boundaries - so a sibling directory whose name merely extends the configured one as a string prefix is not treated as contained. A name that resolves outside the directory is rejected with an IllegalArgumentException before the download call is invoked. The same helper is present on all three branches; it is implemented with java.nio.file only, adds no public API and introduces no new module dependency. Containment was chosen over stripping the path component because Google Cloud Storage keys commonly use a forward slash as a pseudo-directory separator: switching to ${file:onlyname} would have flattened nested names and made distinct objects collide on one local file, whereas containment leaves nested names mapping to sub-directories exactly as before and rejects only what escapes the configured directory. A downloadFileName that already contains an expression is deliberately out of scope, since that local path is constructed by the route author, who is trusted under the Camel security model. 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 for the generic and remote file consumers, and CAMEL-23942 for the Azure Storage download paths.

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, set the filter option to a regular expression that accepts only simple single-segment object names, so that any name carrying a path separator or a parent-directory segment is excluded before an exchange is created; note that no filtering whatsoever is applied when the option is left unset, and that the expression is matched against the whole object name. Alternatively, give downloadFileName an explicit expression that does not carry the remote path through, for example one built on ${file:onlyname} rather than the implicit ${file:name}, keeping in mind that a downloadFileName containing an expression is treated as route-author-controlled and is not covered by the containment check added in the fix. As defence in depth, treat the object names in any externally writable bucket as untrusted input and do not derive local filesystem paths from them.

Credit

Reported by n0mi1k

References

PGP signed advisory data: CVE-2026-66907.txt.asc
Mitre CVE Entry: https://www.cve.org/CVERecord?id=CVE-2026-66907