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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.

PUBLISHED Reserved 2026-05-08 | Published 2026-05-11 | Updated 2026-05-11 | Assigner VulnCheck




MEDIUM: 5.4CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

HIGH: 7.3CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Problem types

Inclusion of Functionality from Untrusted Control Sphere

Product status

Default status
unaffected

Any version before 2026.4.20
affected

2026.4.20 (semver)
unaffected

Credits

Gus (@garagon) reporter

References

github.com/...enclaw/security/advisories/GHSA-mj59-h3q9-ghfh (GitHub Security Advisory (GHSA-mj59-h3q9-ghfh)) vendor-advisory

github.com/...ommit/62fa5071896e95edc7f67d1cebc70a2859e283af (Patch Commit (1)) patch

github.com/...ommit/85d86ebc4bf3d2226d39d132a484f4f7a299fa1b (Patch Commit (2)) patch

www.vulncheck.com/...ion-via-mcp-stdio-environment-variables (VulnCheck Advisory: OpenClaw < 2026.4.20 - Arbitrary Code Execution via MCP stdio Environment Variables) third-party-advisory

cve.org (CVE-2026-44995)

nvd.nist.gov (CVE-2026-44995)

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