Affected: QWED-AI qwed-verification

QWED is open-source AI verification infrastructure for deterministic verification of LLM outputs, tool calls, code, schemas, and agent state before production execution. Prior to 5.1.2, the qwed package passes caller-controlled math expressions directly to SymPy parse_expr() without restricted global_dict and local_dict namespaces, allowing Python eval() to resolve builtins and execute arbitrary Python code in the API server process. In src/qwed_new/api/main.py, POST /verify/math is protected by get_current_tenant but accepts any valid tenant API key, reads the expression field, applies only a cosmetic re.sub(r'(\d)(()', r'\1*\2', expression) normalization, and passes the result to parse_expr(). In src/qwed_new/core/batch.py, POST /verify/batch sends math items through batch_service.create_job(), stores item.query verbatim, and _verify_item() passes VerificationType.MATH input to parse_expr() without sanitization. The default-enabled POST /auth/signup endpoint allows anyone to create a standard tenant account, POST /auth/api-keys issues an x-api-key, and either vulnerable path can then be used to read or write files, modify data, execute operating system commands, terminate the service, and compromise other tenants in a shared deployment. This issue is fixed in version 5.1.2.

Affected: PyPI: qwed

### Summary

The `qwed` package (version 5.1.1) passes attacker-controlled input directly to SymPy's `parse_expr()` function without a restricted namespace. Because `parse_expr()` internally calls Python's `eval()`, any authenticated tenant can execute arbitrary Python code inside the API server process. The attack requires only a standard user account, which is freely obtainable through the default-enabled `/auth/signup` endpoint. Successful exploitation gives the attacker full read/write access to the filesystem and the ability to execute operating system commands, resulting in complete server compromise.

### Details

The vulnerability exists in two independently reachable code paths:

**Primary sink — `POST /verify/math`**

`src/qwed_new/api/main.py:442` defines the `/verify/math` route, protected only by `get_current_tenant` (line 444), which accepts any valid tenant API key. The request body field `expression` is read at line 463 and passed through a cosmetic regex normalization at line 495 (`re.sub(r'(\d)(\()', r'\1*\2', expression)`) that performs no security validation. The normalized string is then passed directly to `parse_expr()` at line 504:

```python # src/qwed_new/api/main.py expression = request.get("expression") ... expression_normalized = re.sub(r'(\d)(\()', r'\1*\2', expression) ... parsed = parse_expr(expression_normalized) # line 504 — unsandboxed eval ```

**Secondary sink — `POST /verify/batch`**

`src/qwed_new/api/main.py:1481` defines the `/verify…