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PatchSiren cyber security CVE debrief

CVE-2026-40217 BerriAI CVE debrief

CVE-2026-40217 is a high-severity vulnerability in LiteLLM, allowing remote attackers to execute arbitrary code via bytecode rewriting at the /guardrails/test_custom_code URI. The vulnerability has a CVSS score of 8.8 and is classified as HIGH. It was published on April 10, 2026, and last modified on June 30, 2026. The vulnerability affects LiteLLM versions up to 2026-04-08. There is no evidence of ransomware campaign use. Users should update to the latest version of LiteLLM to mitigate this vulnerability.

Vendor
BerriAI
Product
LiteLLM
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-10
Original CVE updated
2026-07-15
Advisory published
2026-04-10
Advisory updated
2026-07-15

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40217 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40217

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-40217 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40217

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://www.x41-dsec.de/lab/advisories/x41-2026-001-litellm/

    [email protected] - Exploit, Mitigation, Third Party Advisory

  • Source reference

    Unverified legacy reference

    URL: https://access.redhat.com/errata/RHSA-2026:24866

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

  • Source reference

    Unverified legacy reference

    URL: https://access.redhat.com/errata/RHSA-2026:30056

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

  • Source reference

    Unverified legacy reference

    URL: https://access.redhat.com/security/cve/CVE-2026-40217

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

  • Source reference

    Unverified legacy reference

    URL: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40217.json

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.