SB2026050723 - Sandbox escape in custom-code guardrail in LiteLLM
Published: May 7, 2026
Security Bulletin ID
SB2026050723
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper Control of Dynamically-Managed Code Resources (CVE-ID: CVE-2026-40217)
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to improper control of dynamically-managed code resources in the POST /guardrails/test_custom_code endpoint when running user-supplied Python inside a hand-rolled sandbox. A remote privileged user can submit crafted Python code to execute arbitrary code.
In default configurations, reaching the endpoint requires a proxy-admin credential. The proxy process runs as root in the default Docker image.
Remediation
Install update from vendor's website.