Browserbase Autobrowse Trace Artifact default permission

A local attacker on the same host, workspace, container mount, or shared filesystem where Browserbase Skills Autobrowse trace artifacts are stored can read trace files because they are written with default filesystem permissions [ref_id=1]. The trace artifact handler uses `fs.writeFileSync` without explicitly setting restrictive file modes, so the resulting permissions depend on the host process umask and parent directory permissions [ref_id=1]. In shared development environments, CI workspaces, multi-user systems, or container-mounted volumes, these files may become group-readable or world-readable, allowing another local user or process to access sensitive trace data [ref_id=1].

The advisory recommends setting restrictive permissions when creating trace directories and writing trace files, such as using `0o700` for directories and `0o600` for files, but no patch has been published because the vendor did not respond to the disclosure [ref_id=1]. Without an explicit fix, the vulnerability remains open; users must manually harden their environments by adjusting umask settings or applying restrictive permissions to trace artifact directories and files [ref_id=1].

The public PoC script at https://github.com/NARKHEDE-VAIBHAV/poc/blob/main/CVE-2026-12823%20-%20Browserbase%20Skills%20Autobrowse%20Trace%20Artifact%20Insecure%20File%20Permissions/poc.sh demonstrates the issue by creating trace files with default permissions and then checking whether they are readable by another local user.