Unsandboxed Script Evaluators Turn Workflows Into Shells
A critical unauthenticated remote code execution flaw in Orkes Conductor, a workflow orchestration platform, is under active exploitation, according to Fortinet. Tracked as CVE-2026-58138 (CVSS 3.1: 9.8, CVSS 4.0: 9.3), the bug lets attackers execute arbitrary OS commands by submitting malicious workflow definitions to the platform's API — with no login required.
The root cause: Conductor's INLINE, LAMBDA, DO_WHILE, and SWITCH task types evaluate JavaScript or Python expressions using unsandboxed GraalVM evaluators configured with HostAccess.ALL or allowAllAccess(true). Those settings hand submitted scripts full access to the host JVM rather than isolating them, so a crafted workflow definition submitted straight to the API can break out of the intended scripting sandbox and run arbitrary commands on the underlying server.
Scale of Exploitation
Fortinet's Outbreak Alerts telemetry shows the attack ramping up quickly:
- 1,290 attack attempts blocked in a single 24-hour period as of September 9, 2026 — a 132% day-over-day increase
- Nearly 7,000 attempts blocked between September 2–9, 2026
- Traffic concentrated from Germany, Hong Kong, Indonesia, the UAE, and India
No authentication, prior access, or user interaction is needed — any internet-facing Conductor API endpoint accepting workflow submissions is a viable target.
Affected Versions
| Product | Affected | Fixed |
|---|---|---|
| Orkes Conductor | 3.21.21 through 3.30.1 | 3.30.2+ |
Remediation
- Upgrade to Orkes Conductor 3.30.2 or later immediately.
- Restrict external network access to workflow API endpoints — do not expose them directly to the internet.
- Monitor for suspicious workflow submissions, particularly INLINE/LAMBDA/DO_WHILE/SWITCH task definitions containing unexpected script content, and watch for unexpected command execution originating from the Conductor process.
- Where upgrading isn't immediately possible, place the API behind network access controls limited to trusted internal systems.