Executive brief
microsandbox is a sandboxing framework that spawns isolated child processes for untrusted code execution. The SDK passes sensitive configuration data (API keys, network secrets, and environment variables) as command-line arguments to the sandbox process, making them visible to any local user on the host via the process listing. An attacker with local access can read these secrets without elevated privileges, potentially compromising credentials meant to remain host-side.
Technical details
The vulnerability is an information disclosure (CWE-200, CWE-214) in how microsandbox passes configuration to spawned sandbox processes. In `sdk/rust/lib/runtime/spawn.rs`, the entire `NetworkConfig` and per-sandbox environment variables are serialized and passed as command-line arguments (`--network-config <json>` and `--env KEY=VALUE`). On Linux, process arguments are world-readable via `/proc/<pid>/cmdline` and on all platforms visible via `ps`, allowing any unprivileged local user to read secrets directly from the process table. The fix involves passing sensitive configuration via inherited file descriptors (`--network-config-fd`) rather than argv, following the existing `--parent-watch-fd` pattern. No special privileges, user interaction, or code execution inside the sandbox is required; exploitation is purely host-side.
Affected products
- microsandbox SDK
Timeline
- 2026-09-22: disclosed
- other: CVE-2026-61670 assigned