{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45018","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-08T16:58:28.895Z","datePublished":"2026-08-25T19:18:46.439Z","dateUpdated":"2026-08-25T19:33:30.993Z"},"containers":{"cna":{"title":"Chainlit: Command injection via MCP stdio transport allows unauthenticated remote code execution","problemTypes":[{"descriptions":[{"cweId":"CWE-78","lang":"en","description":"CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":9.8,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/Chainlit/chainlit/security/advisories/GHSA-w3fx-mc44-mf6j","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Chainlit/chainlit/security/advisories/GHSA-w3fx-mc44-mf6j"},{"name":"https://github.com/Chainlit/chainlit/commit/0565fd0eccb915fce159929598b053ed79f6e0c9","tags":["x_refsource_MISC"],"url":"https://github.com/Chainlit/chainlit/commit/0565fd0eccb915fce159929598b053ed79f6e0c9"},{"name":"https://github.com/Chainlit/chainlit/blob/2.12.0/docs/security-advisory-2026-mcp.md#spl-2026-001--command-injection-via-mcp-stdio","tags":["x_refsource_MISC"],"url":"https://github.com/Chainlit/chainlit/blob/2.12.0/docs/security-advisory-2026-mcp.md#spl-2026-001--command-injection-via-mcp-stdio"},{"name":"https://github.com/Chainlit/chainlit/releases/tag/2.12.0","tags":["x_refsource_MISC"],"url":"https://github.com/Chainlit/chainlit/releases/tag/2.12.0"}],"affected":[{"vendor":"Chainlit","product":"chainlit","versions":[{"version":">= 2.4.0rc0, < 2.12.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-25T19:18:46.439Z"},"descriptions":[{"lang":"en","value":"Chainlit is a Python framework for building production-ready conversational AI applications. From 2.4.0rc0 until 2.12.0, Chainlit deployments with features.mcp.enabled set to true in .chainlit/config.toml expose the POST /mcp endpoint without requiring authentication. For stdio transport, the endpoint accepts a user-controlled fullCommand string. The validate_mcp_command() function in backend/chainlit/mcp.py checks only the executable name against config.features.mcp.stdio.allowed_executables and passes unchecked arguments to StdioServerParameters in backend/chainlit/server.py. Because npx supports the -c argument, an attacker can execute arbitrary shell commands with the privileges of the Chainlit process. If allowed_executables is unset, its None default is treated as allowing every executable. This issue is fixed in version 2.12.0."}],"source":{"advisory":"GHSA-w3fx-mc44-mf6j","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/Chainlit/chainlit/security/advisories/GHSA-w3fx-mc44-mf6j","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T19:33:08.662498Z","id":"CVE-2026-45018","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-25T19:33:30.993Z"}}]}}