{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-40217/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[{"cvss":8.8,"id":"CVE-2026-40217"}],"_cs_exploited":false,"_cs_products":[],"_cs_severities":["critical"],"_cs_tags":["CVE-2026-40217","litellm","rce","bytecode-rewriting"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eLiteLLM, a library for simplifying interactions with Large Language Models (LLMs), is vulnerable to remote code execution (RCE) through version 2026-04-08. The vulnerability, identified as CVE-2026-40217, exists due to insufficient input validation at the \u003ccode\u003e/guardrails/test_custom_code\u003c/code\u003e URI. A remote attacker can exploit this flaw by rewriting bytecode, effectively injecting and executing arbitrary code on the server hosting LiteLLM. This vulnerability poses a significant risk, as it allows unauthenticated attackers with network access to the affected server to gain complete control.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker identifies a LiteLLM instance running a vulnerable version (\u0026lt;= 2026-04-08) with the \u003ccode\u003e/guardrails/test_custom_code\u003c/code\u003e endpoint exposed.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious HTTP request targeting the \u003ccode\u003e/guardrails/test_custom_code\u003c/code\u003e URI.\u003c/li\u003e\n\u003cli\u003eThe malicious request includes specially crafted data designed to rewrite the bytecode executed by the LiteLLM instance.\u003c/li\u003e\n\u003cli\u003eThe LiteLLM application, due to the vulnerability, processes the attacker-supplied data without proper sanitization or validation.\u003c/li\u003e\n\u003cli\u003eThe application rewrites its own bytecode based on the attacker\u0026rsquo;s input.\u003c/li\u003e\n\u003cli\u003eThe rewritten bytecode contains malicious code injected by the attacker.\u003c/li\u003e\n\u003cli\u003eThe application executes the rewritten bytecode, effectively executing the attacker\u0026rsquo;s injected code.\u003c/li\u003e\n\u003cli\u003eThe attacker gains arbitrary code execution on the server, allowing them to compromise the system, install malware, or exfiltrate data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-40217 allows unauthenticated remote attackers to execute arbitrary code on systems running vulnerable versions of LiteLLM. This can lead to complete system compromise, including data theft, ransomware deployment, and denial of service. The vulnerability could affect any organization utilizing LiteLLM for LLM interaction, particularly those exposing the vulnerable endpoint to untrusted networks. The impact is rated as critical due to the ease of exploitation and the potential for widespread damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply the necessary patches or upgrade to a version of LiteLLM that addresses CVE-2026-40217 immediately.\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to restrict access to the \u003ccode\u003e/guardrails/test_custom_code\u003c/code\u003e endpoint, as referenced in the vulnerability description.\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rule \u003ccode\u003eDetect LiteLLM Bytecode Rewrite Attempt\u003c/code\u003e to identify potential exploitation attempts targeting the vulnerable endpoint.\u003c/li\u003e\n\u003cli\u003eMonitor web server logs for suspicious POST requests to the \u003ccode\u003e/guardrails/test_custom_code\u003c/code\u003e URI, using the log source specified in the Sigma rule.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-04-11T12:00:00Z","date_published":"2026-04-11T12:00:00Z","id":"/briefs/2026-04-litellm-rce/","summary":"LiteLLM through 2026-04-08 allows remote attackers to execute arbitrary code via bytecode rewriting at the /guardrails/test_custom_code URI, potentially leading to complete system compromise.","title":"LiteLLM Remote Code Execution via Bytecode Rewriting (CVE-2026-40217)","url":"https://feed.craftedsignal.io/briefs/2026-04-litellm-rce/"}],"language":"en","title":"CraftedSignal Threat Feed — CVE-2026-40217","version":"https://jsonfeed.org/version/1.1"}