---
id: CVE-2025-9959
title: >-
  Incomplete validation of dunder attributes allows an attacker to escape from
  the Local Python execution environment sandbox, enforced by smolagents
summary: >-
  Incomplete validation of dunder attributes allows an attacker to escape from
  the Local Python execution environment sandbox, enforced by smolagents. The
  attack requires a Prompt Injection in order to trick the agent to create
  malicious c…
severity: high
cvss: 7.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L'
cwe:
  - CWE-94
published: '2025-09-03'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T00:10:00.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9959'
references:
  - url: 'https://github.com/huggingface/smolagents/pull/1551'
    label: reefs@jfrog.com
  - url: >-
      https://research.jfrog.com/vulnerabilities/smolagents-local-python-sandbox-escape-jfsa-2025-001434277/
    label: reefs@jfrog.com
tags:
  - nvd
epss: 0.00312
epssPercentile: 0.21454
ingestedAt: '2026-09-26T00:22:39.908Z'
---

## Overview

Incomplete validation of dunder attributes allows an attacker to escape from the Local Python execution environment sandbox, enforced by smolagents. The attack requires a Prompt Injection in order to trick the agent to create malicious code.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.