CVE-2026-4039
OpenClaw: Skill env override host env injection via applySkillConfigEnvOverrides (defense-in-depth)
Description
### Summary `applySkillConfigEnvOverrides` previously copied `skills.entries.*.env` values into the host `process.env` without applying the host env safety policy. ### Impact In affected versions, dangerous process-level variables such as `NODE_OPTIONS` could be injected when unset, which can influence runtime/child-process behavior. ### Required attacker capability An attacker must be able to modify OpenClaw local state/config (for example `~/.openclaw/openclaw.json`) to set `skills.entries.<skill>.env` or related skill config values. ### Remediation Fixed in `2026.2.21` by sanitizing skill env overrides and blocking dangerous host env keys (including `NODE_OPTIONS`) before applying overrides, with regression tests covering blocked dangerous keys. ## Fix Commit(s) - `8c9f35cdb51692b650ddf05b259ccdd75cc9a83c` Found using [MCPwner](https://github.com/Pigyon/MCPwner)
How to fix CVE-2026-4039
To remediate CVE-2026-4039, upgrade the affected package to a fixed version below.
- —upgrade to 2026.2.21 or later
Is CVE-2026-4039 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2026.2.21
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |