CVE-2026-47107 describes an incorrect default permissions vulnerability in windmill-labs windmill prior to version 1.703.2. The issue arises because the nsjail sandbox configuration bind-mounts /etc without read-write restrictions, allowing authenticated users executing scripts in the sandbox to write arbitrary entries to critical system files like /etc/hosts, /etc/resolv.conf, and /etc/ssl/certs/ca-certificates.crt. Exploitation can result in persistent poisoning of DNS and SSL trust settings across script executions on the same worker pod. This enables attackers to redirect hostnames, intercept DNS queries, perform transparent HTTPS man-in-the-middle attacks, and capture WM_TOKEN JWTs, which can be used to escalate privileges and access other users' workspaces with admin rights.

The vulnerability allows authenticated users to modify critical system configuration files within the sandbox environment, leading to persistent DNS and SSL poisoning. This can cause hostname redirection, interception of DNS queries, and man-in-the-middle attacks on HTTPS traffic. Additionally, attackers can intercept WM_TOKEN JWTs, enabling them to gain workspace-admin access to other users' workspaces, significantly compromising confidentiality and integrity within the affected environment.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict authenticated user access to the affected versions and avoid running untrusted scripts in the sandbox environment. Monitor vendor communications for updates regarding patches or configuration changes to nsjail sandbox permissions that address this issue.