CVE-2026-47107: Windmill incorrect default permissions in nsjail sandbox configuration

CVE-2026-47107 · Severity: critical · CVSS 9.6 · Published 2026-05-19

Windmill, an open-source developer platform, contained a security flaw in its script execution environment. This vulnerability allowed users with script execution permissions to modify critical system files like network and security certificate configurations. Because these changes could persist on the underlying server, an attacker could intercept data or gain administrative access to other customers' workspaces on the same platform.

Technologies: Windmill Labs Windmill. Vendors: Windmill Labs.

Quick answers

Is CVE-2026-47107 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-47107 being exploited in the wild.
How severe is CVE-2026-47107?
Critical severity, with a CVSS score of 9.6, published 19 May 2026.
Which products and versions are affected?
Windmill Labs Windmill < 1.703.2.
Is there a fix for CVE-2026-47107?
A patch was published on 2026-05-17: Fix merged in PR #9194 and released in v1.703.2 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-47107 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-47107?
Check whether you run Windmill Labs Windmill at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

Windmill's nsjail sandbox configuration incorrectly handled bind-mounts for the /etc directory. While /etc was mounted read-only, Kubernetes submounts for /etc/hosts, /etc/resolv.conf, and /etc/hostname remained writable because nsjail's read-only remount is non-recursive. An authenticated attacker could execute a script to modify these files, persisting 'poisoned' DNS or SSL entries on the long-lived worker pod. This allows for Man-in-the-Middle (MITM) attacks against subsequent jobs from other tenants on the same pod, potentially leading to the interception of WM_TOKEN JWTs and full workspace-admin escalation. The issue is fixed in version 1.703.2 by adding explicit read-only binds for these specific files.

Affected products

  • Windmill Labs Windmill < 1.703.2

Timeline

  • 2026-05-17: patched: Fix merged in PR #9194 and released in v1.703.2
  • 2026-05-19: disclosed: CVE-2026-47107 published

References

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