CVE-2026-47735: Github.com/basekick labs/arc Arc Has An Authenticated Arbitrary Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p2j4-c4g6-rpf5",
  "modified" : "2026-06-08T23:51:19Z",
  "published" : "2026-06-08T23:51:19Z",
  "aliases" : [ "CVE-2026-47735" ],
  "summary" : "Arc has an authenticated arbitrary local-file read via DuckDB I/O functions that bypasses RBAC table-level checks",
  "details" : "### Summary\n\nArc's user-SQL validator (`internal/api/query.go:ValidateSQLRequest`) blocked only `read_parquet(` and `arc_partition_agg(` via regex denylist. The broader DuckDB I/O function family — `read_csv_auto`, `read_csv`, `read_json`, `read_json_auto`, `read_text`, `read_blob`, `glob`, `parquet_metadata`, `parquet_schema`, `read_xlsx`, etc. — was not blocked. RBAC table-reference extraction inspected only `FROM`/`JOIN` clauses, so scalar table functions in the `SELECT` list slipped past both layers.\n\n### Impact\n\nAny authenticated user, including a token with `permissions: []`, can read arbitrary local files via:\n\n```\nPOST /api/v1/query\nAuthorization: Bearer <token>\n{\"sql\": \"SELECT * FROM read_csv_auto('/etc/passwd', header=false, columns={'l':'VARCHAR'}) LIMIT 5\"}\n```\n\nConfirmed reachable targets:\n\n- `auth.db` — bcrypt hashes for every API token, plus legacy SHA-256 rows.\n- `arc.toml` — S3 secrets, TLS keys.\n- `/proc/self/environ` — environment-variable secrets.\n- Cross-tenant Parquet files — bypasses RBAC because the tenant scope is enforced at the table layer, not on raw file paths.\n- SSRF when `httpfs` is loaded (any S3-backed deployment) — `read_csv_auto('http://169.254.169.254/latest/meta-data/...')` reaches instance metadata IPs.\n\n### Patches\n\nFixed in 2026.06.1 (PR #442) via a structural sandbox at the DuckDB layer:\n\n1. `SET GLOBAL allowed_directories = [...]` enumerates Arc's legitimate filesystem prefixes (storage roots + tier prefixes + import upload dir + compaction temp).\n2. `SET GLOBAL enable_external_access = false` (one-way at runtime).\n3. Verified by reading back the flag.\n\nAfter lockdown, DuckDB refuses to open any file outside the allowlist and refuses further `INSTALL`/`LOAD`. Already-loaded extensions remain callable.\n\n### Workarounds\n\n- Restrict API access to known-trusted networks via firewall rules.\n- Temporary mitigation: add `read_csv*`/`read_json*`/`glob` etc. to `dangerousSQLPattern` in `internal/api/query.go` pending 2026.06.1.\n\n### Credits\n\nReported by Alex Manson ([@NeuroWinter](https://github.com/NeuroWinter), https://neurowinter.com/) on 2026-05-19.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/basekick-labs/arc"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.0-20260520141557-91bdc29d1a02"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/Basekick-Labs/arc/security/advisories/GHSA-p2j4-c4g6-rpf5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Basekick-Labs/arc/pull/442"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Basekick-Labs/arc/commit/91bdc29d1a02178ccf8c66375eccf85203108dfb"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Basekick-Labs/arc"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-22", "CWE-918" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-08T23:51:19Z",
    "nvd_published_at" : null
  }
}