CVE-2026-19032: jackson-databind: Path Deserialization Missing Scheme Allowlist for FileSystemProvider Resolution

A java.nio.file.Path field bound from untrusted JSON reaches JDKFromStringDeserializer.NioPathHelper.deserialize. The attacker string flows through new URI(value) → Path.of(uri), then on FileSystemNotFoundException into a ServiceLoader<FileSystemProvider> enumeration that calls provider.getPath(uri) on the first scheme-matching provider. No scheme is rejected, so untrusted JSON can drive an arbitrary registered provider under the default JsonMapper.builder().build().

Impact is bounded. The JDK built-in providers (file, jar/zipfs) do no network I/O and do not mount, so the path is inert without a side-effecting third-party provider. Binding Path from untrusted input is already an anti-pattern.