GHSA-xg6v-cv2h-2w5h: Bake filesystem path entitlements approval can be skipped in some multi-target builds

In Docker Buildx versions v0.19.0 through v0.38.0, an untrusted Bake definition that builds multiple targets together may expose files accessible to the Buildx client without the expected fs.read approval. Under certain conditions, filesystem paths from some targets are not verified against the approved entitlements. Users who run untrusted Bake definitions may be affected. The issue is fixed in v0.38.1.