microsandbox: Secret values exposed in world-readable process arguments

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS

• CVE-2026-61670: 0.16% estimated exploitation activity in the next 30 days; percentile 5.55 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When the SDK spawns a sandbox, the msb sandbox child process receives the full network configuration as an inline --network-config <json command-line argument, and any per-sandbox environment as repeated --env KEY=VALUE arguments. On Linux a process's arguments are world-readable via /proc/<pid/cmdline, and on both Linux and macOS they are visible to other local processes via ps. Because the network configuration carries the real secret values used for host-side secret substitution, any unprivileged local user (or any process running as a different user on the same host) can read those secrets directly out of the process listing for as long as the sandbox is running. This defeats the "secrets that can't leak" guarantee for the host side of the boundary. Details The SDK serializes the entire NetworkConfig, including the real (non-placeholder) secret values, and pushes it onto the child argv, in sdk/rust/lib/runtime/spawn.rs near line 1241: The CLI accepts it only as an inline…

Published by the source

22 Sep 2026, 19:43 UTC

Last modified by the source

22 Sep 2026, 20:00 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m8f5-rh7h-vgg3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-m8f5-rh7h-vgg3

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# Patch Next advisory brief: CVE-2026-61670

Advisory: microsandbox: Secret values exposed in world-readable process arguments
IDs: CVE-2026-61670, GHSA-m8f5-rh7h-vgg3
Record: https://patchnext.com/advisories/cve-2026-61670 (revision 2, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: microsandbox 0.5.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io microsandbox: affected < 0.5.10; fixed in 0.5.10

## Suggested inspection (read-only)
- crates.io microsandbox: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on microsandbox.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m8f5-rh7h-vgg3 (OSV record GHSA-m8f5-rh7h-vgg3 lists affected ranges: crates.io microsandbox >=0 <0.5.10 (fixed))
- Verified: https://github.com/advisories/GHSA-m8f5-rh7h-vgg3 (GitHub-reviewed advisory GHSA-m8f5-rh7h-vgg3 lists affected ranges: crates.io microsandbox >=0 <0.5.10)

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