CVE-2026-40217 BerriAI CVE debrief

Who should care

Organizations using LiteLLM should prioritize patching this vulnerability to prevent remote code execution attacks. The vulnerability's high severity and potential for exploitation make it essential for defenders to take immediate action. Additionally, security teams should review their inventory of affected systems and ensure that all instances are updated.

Technical summary

CVE-2026-40217 is a remote code execution vulnerability in LiteLLM, caused by bytecode rewriting at the /guardrails/test_custom_code URI. The vulnerability has a CVSS vector of CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating a high level of exploitability and impact. The CWE-420 and CWE-94 weaknesses are associated with this vulnerability. The vulnerability affects LiteLLM versions up to 2026-04-08, and users should update to the latest version to mitigate this vulnerability.

Defensive priority

High priority should be given to patching this vulnerability, as it allows remote code execution and has a high CVSS score. Defenders should review their inventory of affected systems and ensure that all instances are updated.

Recommended defensive actions

• Update LiteLLM to the latest version to mitigate this vulnerability.
• Review inventory of affected systems and ensure that all instances are updated.
• Monitor for potential exploitation attempts.
• Implement compensating controls, such as web application firewalls, to detect and prevent attacks.
• Perform regular vulnerability scans to identify and address potential vulnerabilities.

Evidence notes

The vulnerability was published on April 10, 2026, and last modified on June 30, 2026. The CVSS score is 8.8, and the vulnerability is classified as HIGH. The CWE-420 and CWE-94 weaknesses are associated with this vulnerability. There is no evidence of ransomware campaign use.

Official resources