Which versions of Windmill are affected by EUVD-2026-16820?

Windmill versions prior to 1.664.0 contain a code injection vulnerability in the NativeTS executor that allows workspace administrators to execute arbitrary code across all TypeScript scripts within…. A patch is available.

How to fix or mitigate EUVD-2026-16820?

Within 24 hours: Identify all Windmill installations and document current versions. Within 7 days: Upgrade all affected Windmill instances to version 1.664.0 or later. Within 30 days: Audit workspace administrator accounts and review recent script modifications for suspicious activity; implement principle of least privilege for workspace admin role assignments.

Windmill EUVD-2026-16820

Q: What is the CVSS score of EUVD-2026-16820?

EUVD-2026-16820 has a CVSS 4.0 base score of 7.3 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

| CVE-2026-33881 HIGH

Code Injection (CWE-94)

2026-03-27 GitHub_M

Code Injection RCE Windmill

7.3

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.3 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 06:12 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

1.664.0

EUVD ID Assigned

Mar 27, 2026 - 21:15 euvd

EUVD-2026-16820

Analysis Generated

Mar 27, 2026 - 21:15 vuln.today

CVE Published

Mar 27, 2026 - 20:34 nvd

HIGH 7.3

DescriptionGitHub Advisory

Windmill is an open-source developer platform for internal code: APIs, background jobs, workflows and UIs. Workspace environment variable values are interpolated into JavaScript string literals without escaping single quotes in the NativeTS executor. A workspace admin who sets a custom environment variable with a value containing ' can inject arbitrary JavaScript that executes inside every NativeTS script in that workspace. This is a code injection bug in worker.rs, not related to the sandbox/NSJAIL topic. Version 1.664.0 patches the issue.

AnalysisAI

JavaScript code injection in Windmill's NativeTS executor allows workspace administrators to achieve remote code execution by embedding malicious payloads in environment variable values. The vulnerability (CWE-94) stems from improper sanitization of single quotes when interpolating workspace environment variables into JavaScript string literals, enabling arbitrary code execution in all NativeTS scripts within the affected workspace. Windmill versions prior to 1.664.0 are affected. CVSS 7.3 reflects high confidentiality, integrity, and availability impact, though exploitation requires high privileges (workspace admin role). Publicly available exploit code exists, though no confirmed active exploitation (CISA KEV) at time of analysis.

Technical ContextAI

Windmill is an open-source developer platform (cpe:2.3:a:windmill-labs:windmill) for building internal tools, APIs, workflows, and background jobs. The NativeTS executor runs TypeScript/JavaScript code in a sandboxed environment. The vulnerability exists in worker.rs where workspace environment variables are interpolated into JavaScript string literals without proper escaping. CWE-94 (Improper Control of Generation of Code / Code Injection) occurs when untrusted data flows into executable code contexts without validation. In this case, a workspace admin setting an environment variable like ENV_VAR='foo'; maliciousCode(); var x=' would break out of the intended string literal boundary. The single quote character acts as a delimiter escape, allowing injection of arbitrary JavaScript that executes with the privileges of the NativeTS runtime across all scripts in that workspace. This is distinct from sandbox escape vulnerabilities and represents a pre-sandbox code generation flaw.

RemediationAI

Upgrade to Windmill version 1.664.0 or later, which implements proper escaping of single quotes and other special characters during environment variable interpolation into JavaScript string literals. The vendor-released patch addresses the root cause in worker.rs by sanitizing user-controlled input before code generation. Organizations should prioritize this upgrade for any workspace where administrator roles are assigned to users beyond the core security team. Immediate mitigation steps for environments unable to upgrade include restricting workspace administrator permissions to only highly trusted personnel, auditing existing environment variable values for suspicious payloads (search for single quotes followed by semicolons or JavaScript keywords), and implementing monitoring for unusual NativeTS script behavior. After upgrading, review workspace environment variables and rotate any credentials that may have been exposed if exploitation is suspected. Full remediation guidance and patch details are documented in the GitHub Security Advisory at https://github.com/windmill-labs/windmill/security/advisories/GHSA-8q8j-mm3g-5c2q.