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

Severity: low (CVSS 2.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-20 · updated 2026-06-17
Weakness: CWE-200

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.

Affected products

windmill-labs windmill: before 1.635.0 — fixed in 1.635.0

How to fix

Upgrade to a fixed version: windmill-labs windmill 1.635.0. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-26964 or the next vulnerability affects your stack