CVE-2026-26964 Windmill Exposes Workspace Slack OAuth Client Secrets to Non-Admin Workspace Members

Low 2.7 Published 19 Feb 2026 Updated 20 Feb 2026

Non-admin users can retrieve Slack OAuth client secrets via an API endpoint, exposing sensitive credentials to unauthorized personnel.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-26964?

CVE-2026-26964 is a low-severity vulnerability in windmill-labs windmill, published on 19 Feb 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

Windmill is an open-source developer platform for internal code: APIs, background jobs, workflows and UIs. Versions 1.634.6 and below allow non-admin users to obtain Slack OAuth client secrets, which should only be accessible to workspace administrators. The GET /api/w/{workspace}/workspaces/get_settings endpoint returns the slack_oauth_client_secret to any authenticated workspace member, regardless of their admin status. It is expected behavior for non-admin users see a redacted version of workspace settings, as some of them are necessary for the frontend to behave correctly even for non-admins. However, the Slack configuration should not be visible to non-admins. This is a legacy issue where the setting was stored as a plain value instead of using $variable indirection, and it was never added to the redaction logic. This issue has been fixed in version 1.635.0.

Weakness: CWE-200

Which versions are affected by CVE-2026-26964?

It affects 1 product.

Products include Windmill Windmill.

How do I fix CVE-2026-26964?

No fix has been published for CVE-2026-26964 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-26964 being exploited?

There is no known exploitation of CVE-2026-26964 in the wild and no public exploit code.

Sources

Also known as GHSA-f27g-j463-q85w.