Code Injection in Windmill - CVE-2026-33881
Published: April 28, 2026
Vulnerability identifier: #VU128315
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-33881
CWE-ID: CWE-94
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to inject arbitrary JavaScript code.
The vulnerability exists due to improper control of code generation in the NativeTS executor in backend/windmill-worker/src/worker.rs when interpolating workspace environment variable values into JavaScript string literals. A remote user can set a crafted workspace environment variable value containing a single quote to inject arbitrary JavaScript code.
The injected code executes inside every NativeTS script in the workspace as the executing user and can access reserved variables such as WM_TOKEN and WM_EMAIL.
Affected software
Windmill
How to mitigate CVE-2026-33881
Install security update from vendor's website.
Windmill - update to 1.664.0