The vulnerability is a missing authorization check that allows users with the Operator role to create and modify entities such as scripts, flows, apps, and raw_app objects through the backend API. Operators are documented and priced as unable to perform those actions, yet the API enforces the restriction only on selected endpoints, leaving operators able to add or update scripts. Because operators can execute scripts via the jobs API, the flaw permits an attacker to gain full code execution on the Windmill deployment. This results in complete compromise of confidentiality, integrity, and availability of the system.

Windmill releases from version 1.56.0 up to, but not including, 1.615.0 are affected. This includes the Windmill Community Edition (CE) and Enterprise Edition (EE) from Windmill Labs, as well as the Flow component of Nextcloud. The issue is resolved in release 1.615.0 and later versions. All deployments running a version in the vulnerable range should be upgraded or otherwise mitigated.

The flaw rates a CVSS score of 8.7, indicating a high severity vulnerability. While an EPSS score is not published, the flaw's existence for over a year and its wide applicability to multiple Windmill CMS installations suggest a significant likelihood of exploitation. The attack requires only authenticated access as a user with the Operator role, which may be granted to non‑privileged users. Attackers can exploit the vulnerability over the network by sending crafted API requests to the windmill backend, resulting in remote code execution. The vulnerability is not yet listed in the CISA KEV catalog, but the high CVSS and direct RCE potential warrant immediate remediation.