# CVE-2026-5535: FedML-AI FedML path traversal in MQTT Message Handler

Source: https://junglewise.ai/threats/cve-2026-5535-fedml-ai-fedml-path-traversal-in-mqtt-message-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-05. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-5535 · Severity: medium · CVSS 4.3 · Published 2026-04-05

FedML is an open-source platform used for federated machine learning, allowing different devices to train models collaboratively. A security flaw in its Android training client allows a remote attacker to view the names of files and folders on the device that should be private. This could allow an attacker to map out the device's internal storage and identify sensitive data locations, potentially disrupting operations or aiding further attacks.

Technologies: [Tensoropera Fedml](https://junglewise.ai/threats/technologies/fedml). Vendors: [Tensoropera](https://junglewise.ai/threats/vendors/tensoropera).

## Quick answers

**Is CVE-2026-5535 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-5535 being exploited in the wild.

**How severe is CVE-2026-5535?** Medium severity, with a CVSS score of 4.3, published 5 April 2026.

**Which products and versions are affected?** Tensoropera FedML SDK up to 0.8.9.

**Is there a fix for CVE-2026-5535?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-5535 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-5535?** Check whether you run Tensoropera Fedml or Tensoropera FedML SDK at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A path traversal vulnerability (CWE-22) exists in the FedML Android training client (fedmlsdk) within the FileUtils.java component. The vulnerability is rooted in the MQTT Message Handler, specifically where the 'dataSet' parameter from an incoming MQTT message is used to construct filesystem paths without proper sanitization or canonicalization. An attacker who can publish MQTT messages to the broker can provide a crafted payload (e.g., using '../' sequences) to trigger the File.list() method on unintended directories. This allows for remote directory enumeration and filesystem reconnaissance within the application's sandbox. As of the advisory date, the vendor has not responded to the disclosure.

## Affected products

- FedML-AI (TensorOpera) FedML SDK up to 0.8.9

## Timeline

- 2026-03-18: disclosed: Initial public disclosure of the vulnerability and PoC on GitHub.
- 2026-04-05: advisory: NVD and VulDB publish advisory details.

## References

- [https://github.com/AnalogyC0de/public_exp/issues/25](https://github.com/AnalogyC0de/public_exp/issues/25)
- [https://vuldb.com/submit/782200](https://vuldb.com/submit/782200)
- [https://vuldb.com/vuln/355288](https://vuldb.com/vuln/355288)
- [https://vuldb.com/vuln/355288/cti](https://vuldb.com/vuln/355288/cti)

## Related threats

- [FedML-AI FedML insecure deserialization in gRPC server](https://junglewise.ai/threats/cve-2026-5536-fedml-ai-fedml-insecure-deserialization-in-grpc-server)