Overview
The vulnerability, identified as CVE-2025-9959, is a serious issue that affects the Python execution environment sandbox maintained by smolagents. This is a significant concern as it allows an attacker to escape the sandbox through incomplete validation of dunder attributes, which could potentially lead to system compromise or data leakage.
Vulnerability Summary
CVE ID: CVE-2025-9959
Severity: High (7.6 CVSS score)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
smolagents | All current versions
How the Exploit Works
The exploit works by taking advantage of the incomplete validation of dunder attributes in the smolagents Python execution environment sandbox. The attacker uses a Prompt Injection to trick the agent into creating malicious code, thereby escaping the sandbox.
Conceptual Example Code
A conceptual example of how this vulnerability might be exploited is shown below. This pseudocode demonstrates how an attacker could use a specially crafted string to trick the agent into running a malicious command:
# String with embedded prompt injection
malicious_string = "__import__('os').system('malicious_command')"
# Trick the agent into executing the malicious string
agent.execute(malicious_string)This example shows how the attacker could potentially inject a malicious command into the Python execution environment.
Mitigation
The recommended mitigation is to apply the vendor patch as soon as it’s available. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. It’s crucial to keep these systems up to date and monitor them for any signs of unusual activity.
