CVE-2026-61670: microsandbox: Secret values exposed in world-readable process arguments
microsandbox is an easy, fast, local-first microVM runtime and library. Prior to 0.5.10, sdk/rust/lib/runtime/spawn.rs serializes NetworkConfig secret values into the --network-config argument and passes per-sandbox secrets through repeated --env arguments accepted by crates/cli/lib/sandboxcmd.rs. Other local users or co-resident processes can read these values through the host process table, including /proc process command lines on Linux and process listings on Linux and macOS, for the lifetime of the sandbox. Exploitation does not require code execution inside the sandbox or access to the spawning user's session, and can disclose host-side API keys, tokens, and environment secrets on shared hosts, CI runners, and developer systems. This issue is fixed in version 0.5.10.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
microsandboxto a version that resolves this vulnerability.Fixed in 0.5.10
Event History
Frequently Asked Questions
Which deployments are most exposed to this issue?
Shared hosts, CI runners, and developer systems are specifically exposed because other local users or co-resident processes may be able to inspect host process command lines. The exposure lasts for the lifetime of each sandbox.
What access does an attacker need to retrieve the secrets?
An attacker needs local visibility into the host process table, such as access to /proc process command lines on Linux or process listings on Linux and macOS. They do not need code execution inside the sandbox or access to the spawning user's session.
What kinds of secrets can be disclosed?
NetworkConfig secret values and per-sandbox secrets supplied through environment arguments can be exposed. This can include host-side API keys, tokens, and environment secrets.
How can I determine whether my installation is affected?
Installations running a microsandbox version before 0.5.10 are affected when they launch sandboxes with NetworkConfig secrets or per-sandbox secrets passed through the affected arguments. Version 0.5.10 contains the fix.