# CVE-2026-18948: Feast vulnerable to arbitrary code execution via unsafe deserialization of dill-serialized UDFs

Source: https://junglewise.ai/threats/cve-2026-18948-a-flaw-was-found-in-feast-the-system-improperly-deserializes-user  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-10  
License: CC BY 4.0 with a link back

CVE-2026-18948 · Severity: critical · CVSS 9.9 · Published 2026-08-10

A flaw was found in Feast. The system improperly deserializes user-defined functions (UDFs) stored in its registry, which are serialized using the 'dill' library. This allows a remote attacker to store a malicious UDF, leading to unauthenticated arbitrary code execution on the feature server in default configurations. An authenticated attacker can also achieve arbitrary code execution on the registry server by bypassing authorization checks during deserialization. This vulnerability can result in cross-tenant data access and lateral movement within the system.

Technologies: [feast (PyPI)](https://junglewise.ai/threats/technologies/pypi-feast). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-18948 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18948 being exploited in the wild.

**How severe is CVE-2026-18948?** Critical severity, with a CVSS score of 9.9, published 10 August 2026.

**Which products and versions are affected?** feast (PyPI) < 0.67.0, ECOSYSTEM:introduced=0,fixed=0.67.0.

**Is there a fix for CVE-2026-18948?** Yes. feast (PyPI): upgrade to 0.67.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-18948?** Check whether you run feast (PyPI) 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.

## How to fix

- feast (PyPI): upgrade to 0.67.0 or later

  ```sh
  pip install "feast>=0.67.0"
  ```


## Affected products

- feast (PyPI) < 0.67.0, ECOSYSTEM:introduced=0,fixed=0.67.0

## Identifiers

- CVE-2026-18948
- GHSA-gg2p-37pv-v7fq

## Related threats

- [PYSEC-2026-1367 - Feast Cross-Origin Resource Sharing vulnerability](https://junglewise.ai/threats/cve-2024-11602-feast-cross-origin-resource-sharing-vulnerability)
- [Feast unsafe deserialization in registry server gRPC interface](https://junglewise.ai/threats/cve-2026-56121-feast-unsafe-deserialization-in-registry-server-grpc-interface)
- [Feast remote code execution in Kubernetes materializer job](https://junglewise.ai/threats/cve-2025-11157-feast-remote-code-execution-in-kubernetes-materializer-job)