Executive brief
Windmill is an automation platform used to run scripts and workflows, often integrated into other services like Nextcloud. A security flaw in how it manages folder ownership allows an authorized user to perform unauthorized database queries. By exploiting this, an attacker can steal secret keys used for authentication, impersonate an administrator, and ultimately take full control of the server to execute malicious code.
Technical details
An SQL injection vulnerability exists in Windmill's folder ownership management functionality due to improper neutralization of the 'owner' parameter. Authenticated attackers can exploit this flaw to perform unauthorized database queries, enabling the extraction of sensitive information such as JWT signing secrets and administrative user IDs. With these secrets, an attacker can forge administrative tokens to bypass authentication and access workflow execution endpoints. This leads to Remote Code Execution (RCE) by executing arbitrary scripts within the workflow engine. The vulnerability affects Windmill versions 1.276.0 through 1.603.2 and Nextcloud Flow versions 1.0.0 through 1.2.2. Patches are available in Windmill v1.603.3 and Nextcloud Flow v1.3.0.
Affected products
- Windmill Labs Windmill CE (Community Edition) 1.276.0 - 1.603.2
- Windmill Labs Windmill EE (Enterprise Edition) 1.276.0 - 1.603.2
- Nextcloud Nextcloud Flow 1.0.0 - 1.2.2
Timeline
- 2026-04-06: disclosed: Initial researcher blog post published
- 2026-04-07: advisory: CVE-2026-23696 published
- 2026-04-07: patched: Windmill v1.603.3 released
References
- https://apps.nextcloud.com/apps/flow/releases
- https://chocapikk.com/posts/2026/windfall-nextcloud-flow-windmill-rce/
- https://github.com/Chocapikk/Windfall
- https://github.com/windmill-labs/windmill/commit/942fb629210ebb287f48467d1535ffde3a3eeafe
- https://github.com/windmill-labs/windmill/releases/tag/v1.603.3
- https://www.vulncheck.com/advisories/windmill-file-ownership-handling-sqli-rce
- https://www.windmill.dev/