GHSA-45cg-2683-gfmq

## Impact

`assertBrowserNavigationAllowed()` validated only `http:`/`https:` network targets but implicitly allowed other schemes. An authenticated gateway user could navigate browser sessions to `file://` URLs and read local files via browser snapshot/extraction flows.

## Affected Component

- `src/browser/navigation-guard.ts`

## Technical Reproduction

1. Authenticate to a gateway that has browser tooling enabled. 2. Invoke browser navigation with a `file://` URL (for example `file:///etc/passwd`). 3. Read page content through browser snapshot/extract actions.

## Demonstrated Impact

An attacker with valid gateway credentials and browser-tool access can exfiltrate local files readable by the OpenClaw process user (for example config/secrets in that user context).

## Environment

- OpenClaw browser tool enabled - Attacker has authenticated access capable of invoking browser actions

## Remediation Advice

Reject unsupported navigation schemes and allow only explicitly safe non-network URLs. OpenClaw now blocks non-network schemes (such as `file:`, `data:`, and `javascript:`) while preserving `about:blank`.

## Affected Packages / Versions

- Package: `openclaw` (npm) - Affected versions: `<= 2026.2.19-2` - Patched in planned next release: `2026.2.21`

## Fix Commit(s)

- `220bd95eff6838234e8b4b711f86d4565e16e401`

## Release Process Note

`patched_versions` is pre-set to the planned next release (`2026.2.21`) so once npm `2026.2.21` is published, the advisory can be published directly.

OpenClaw thanks @q1uf3ng for reporting.