{"id":"CVE-2026-40159","aliases":["GHSA-pj2r-f9mw-vrcq","PYSEC-2026-2918"],"url":"https://o3.security/vulnerability/CVE-2026-40159","summary":"PraisonAI Exposes Sensitive Environment Variable via Untrusted MCP Subprocess Execution","details":"PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI’s MCP (Model Context Protocol) integration allows spawning background servers via stdio using user-supplied command strings (e.g., MCP(\"npx -y @smithery/cli ...\")). These commands are executed through Python’s subprocess module. By default, the implementation forwards the entire parent process environment to the spawned subprocess. As a result, any MCP command executed in this manner inherits all environment variables from the host process, including sensitive data such as API keys, authentication tokens, and database credentials. This behavior introduces a security risk when untrusted or third-party commands are used. In common scenarios where MCP tools are invoked via package runners such as npx -y, arbitrary code from external or potentially compromised packages may execute with access to these inherited environment variables. This creates a risk of unintended credential exposure and enables potential supply chain attacks through silent exfiltration of secrets. This vulnerability is fixed in 4.5.128.","published":"2026-04-10T16:57:11.623Z","modified":"2026-08-07T11:50:17.056294703Z","cvss":{"score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"},"epss":{"score":0.00182,"percentile":0.07947,"asOf":"2026-08-06"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"praisonai","fixedVersion":"4.5.128"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40159.json"},{"type":"ADVISORY","url":"https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-pj2r-f9mw-vrcq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40159"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:17.056294703Z"}}