OpenClaw < 2026.4.20 - Arbitrary Code Execution via MCP stdio Environment Variables | Advisories

Advisories

OpenClaw < 2026.4.20 - Arbitrary Code Execution via MCP stdio Environment Variables

severity: high
date: 5/11/2026
Affecting: OpenClaw < 2026.4.20
CVE: CVE-2026-44995
CWE: CWE-829 Inclusion of Functionality from Untrusted Control Sphere
CVSS: 5.4
CVSS V4 Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References: GitHub Security Advisory (GHSA-mj59-h3q9-ghfh)
Patch Commit (1)
Patch Commit (2)
Credit: Gus (@garagon)
Description: OpenClaw before 2026.4.20 contains an improper environment variable validation vulnerability in MCP stdio server configuration that allows attackers to execute arbitrary code. Malicious workspace configurations can pass dangerous startup variables like NODE_OPTIONS, LD_PRELOAD, or BASH_ENV to spawned MCP server processes, enabling code injection when operators start sessions using those servers.

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