Which versions of Nextcloud are affected by EUVD-2026-19747?

Windmill versions 1.56.0 through 1.614.0 contain a critical authorization bypass that allows users with Operator roles to escalate privileges and execute arbitrary code on self-hosted instances.

Is there a public PoC exploit available for EUVD-2026-19747?

Yes, a public proof-of-concept exploit is available for EUVD-2026-19747. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate EUVD-2026-19747?

Within 24 hours: Identify all Windmill deployments in your environment and determine if any run versions 1.56.0-1.614.0; audit all Operator role assignments and document which accounts hold this privilege. Within 7 days: Restrict network access to affected Windmill instances to trusted internal networks only; restrict or revoke Operator role assignments to essential personnel only, applying least-privilege principles. Within 30 days: Contact Windmill vendor for availability of patched versions; upgrade to the latest available version once released, or evaluate migration to alternative orchestration platforms if patches remain unavailable.

Nextcloud EUVD-2026-19747

Q: What is the CVSS score of EUVD-2026-19747?

EUVD-2026-19747 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/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: 0.2%.

| CVE-2026-22683 HIGH

Missing Authorization (CWE-862)

2026-04-07 disclosure@vulncheck.com

GHSA-9q9g-rp9x-244h

Authentication Bypass Privilege Escalation RCE Nextcloud Windmill Flow

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/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 NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

Apr 24, 2026 - 16:52 vuln.today

cvss_changed

PoC Detected

Apr 08, 2026 - 21:27 vuln.today

Public exploit code

EUVD ID Assigned

Apr 07, 2026 - 17:22 euvd

EUVD-2026-19747

Analysis Generated

Apr 07, 2026 - 17:22 vuln.today

CVE Published

Apr 07, 2026 - 17:16 nvd

HIGH 8.7

DescriptionCVE.org

Windmill versions 1.56.0 through 1.614.0 contain a missing authorization vulnerability that allows users with the Operator role to perform prohibited entity creation and modification actions via the backend API. Although Operators are documented and priced as unable to create or modify entities, the API does not enforce the Operator restriction on workspace endpoints, allowing an Operator to create and update scripts, flows, apps, and raw_apps. Since Operators can also execute scripts via the jobs API, this allows direct privilege escalation to remote code execution within the Windmill deployment. This vulnerability has existed since the introduction of the Operator role in version 1.56.0.

AnalysisAI

Authorization bypass in Windmill 1.56.0-1.614.0 enables Operator role users to escalate privileges to remote code execution. Operators can bypass documented role restrictions via unprotected backend API endpoints to create/modify scripts, flows, and apps, then execute arbitrary code through the jobs API. Public exploit code exists (GitHub: Chocapikk/Windfall). EPSS data unavailable, but the low attack complexity (AC:L), network access vector (AV:N), and availability of weaponized POC indicate elevated real-world risk for self-hosted Windmill deployments with Operator-level users.

Technical ContextAI

Windmill is an open-source developer platform for building internal tools and workflows. The Operator role, introduced in version 1.56.0, is designed as a restricted tier that can execute but not create or modify entities (scripts, flows, apps). This vulnerability stems from CWE-862 (Missing Authorization), where workspace API endpoints fail to enforce role-based access controls. The backend API permits HTTP requests from Operator-authenticated sessions to perform POST/PUT operations on resource creation and modification endpoints without validating the caller's permission level. Because Operators retain legitimate access to the jobs execution API, successful entity creation immediately enables code execution within the Windmill runtime environment, typically a containerized Python/TypeScript/Bash execution context.

RemediationAI

Upgrade immediately to Windmill version 1.615.0 or later, which implements proper authorization checks on workspace API endpoints via commit c621a74804f4f6e8318819c01e3a23a17698588b. The patch enforces Operator role restrictions at the API layer to prevent entity creation and modification. For environments unable to upgrade immediately, temporary mitigations include removing Operator role assignments and reverting affected users to viewer-only roles, implementing reverse proxy or API gateway rules to block PUT/POST requests to /api/w/{workspace}/scripts, /api/w/{workspace}/flows, and /api/w/{workspace}/apps endpoints for Operator-authenticated sessions, and enabling comprehensive API audit logging to detect unauthorized entity creation attempts. Review access logs since deployment of version 1.56.0 for suspicious script/flow creation by Operator accounts. Full remediation guidance is available in the release notes at https://github.com/windmill-labs/windmill/releases/tag/v1.615.0 and the technical writeup at https://chocapikk.com/posts/2026/windfall-nextcloud-flow-windmill-rce/.