OpenClaw: Zip extraction symlink traversal could write outside destination

Summary

### Summary A path confinement bypass in OpenClaw ZIP extraction allowed writes outside the intended destination when a pre-existing symlink was present under the extraction root.

### Affected Packages / Versions - Package: `openclaw` (npm) - Latest published npm version at triage time: `2026.2.21-2` - Affected versions: `<= 2026.2.21-2` - Planned patched version for next release: `2026.2.22`

### Technical Details The vulnerable path was in `src/infra/archive.ts` ZIP extraction logic. Output-path checks were lexical, but writes could still traverse an existing symlink in destination path segments.

The fix blocks this by: - rejecting symlink traversal in destination path segments, - validating resolved destination paths remain inside the extraction root, - using no-follow file opens for ZIP output writes where supported, - adding a regression test for pre-seeded destination symlink traversal.

### Impact - Type: Arbitrary file write outside extraction root via symlink traversal during ZIP extraction. - Preconditions: attacker-controlled archive extraction plus pre-existing symlink in destination path.

### Fix Commit(s) - 4b226b74f5fd3b106a83a6347fd404172e2fd246

### Release Process Note Patched version is pre-set to the planned next release (`2026.2.22`). Once npm release `2026.2.22` is published, the advisory can be published without further field edits.

OpenClaw thanks @tdjackey for reporting.