Authorizer: CQL/N1QL Injection in Cassandra and Couchbase Backends via fmt.Sprintf String Interpolation

Summary

## Vulnerability Details

**CWE:** CWE-943 - Improper Neutralization of Special Elements in Data Query Logic

All 66+ CQL queries in `internal/storage/db/cassandradb/` use `fmt.Sprintf` to interpolate user-controlled values directly into CQL query strings without parameterization.

Unauthenticated endpoints (`signup`, `login`, `forgot_password`, `magic_link_login`) pass user input directly into CQL query strings.

**Note:** This advisory covers the Cassandra CQL injection only. The Couchbase N1QL injection is tracked in a separate advisory per CVE rule 4.2.11.

## Affected Code Pattern

```go // Before (VULNERABLE) - e.g. cassandradb/user.go query := fmt.Sprintf("SELECT ... FROM %s WHERE email = '%s'", table, email) err := p.db.Query(query).Scan(...) ```

## Steps to Reproduce

1. Deploy Authorizer <= 2.0.0 with Cassandra backend 2. Send a signup request with a CQL injection payload in the email field:

```bash curl -X POST http://localhost:8080/graphql \ -H 'Content-Type: application/json' \ -d '{"query":"mutation { signup(params: { email: \"test'\" }) { message } }"}' ```

3. The single quote breaks out of the CQL string literal, causing a CQL parse error that leaks internal schema information 4. Crafted payloads can manipulate query logic to bypass authentication or extract data

## Affected Files (10 Cassandra files)

| Package | File | Queries Fixed | |---------|------|--------------| | cassandradb | user.go | 7 | | cassandradb | otp.go | 4 | | cassandradb | session_token.go | 19 | | cassandradb | verification_requests.go | 4 | | cassandradb | authenticator.go | 3 | | cassandradb | email_template.go | 5 | | cassandradb | webhook.go | 5 | | cassandradb | webhook_log.go | 2 | | cassandradb | session.go | 1 | | cassandradb | env.go | 2 |

## Impact

An unauthenticated attacker can inject arbitrary CQL operators through the email, phone, or token parameters on public-facing endpoints (signup, login, forgot_password, magic_link_login). This enables authentication bypass and data exfiltration from the Cassandra keyspace.

## Proposed Fix

Use parameterized queries:

```go // After (FIXED) query := fmt.Sprintf("SELECT ... FROM %s WHERE email = ?", table) err := p.db.Query(query, email).Scan(...) ```

Fixed in https://github.com/authorizerdev/authorizer/pull/500 (merged 2026-03-27).