GHSA-4hhp-h66f-j5j7

### Summary

`vllm/transformers_utils/processors/mimo_v2_omni.py` — the multimodal processor for `MiMoV2OmniForCausalLM` — issues `requests.get(...)` directly on user-supplied image and audio URL strings and `Image.open(...)` on user-supplied local paths, **without** the SSRF / `allowed_local_media_path` checks that `vllm.multimodal.utils.MediaConnector` was hardened with in **GHSA-qh4c-xf7m-gxfc**, **GHSA-v359-jj2v-j536**, and **GHSA-pf3h-qjgv-vcpr**.

This is the same bug class as those three published advisories, in a code path the patches missed. When a user passes a URL or local-file string through `multi_modal_data` (e.g. `LLM.generate(multi_modal_data={"image": "http://..."})`), the processor takes the unsanitized string and dispatches it without any URL-scheme allowlist, network-target allowlist, size cap, or local-path allowlist.

### Details

**File:** `vllm/transformers_utils/processors/mimo_v2_omni.py` (current `main`)

**Sink 1 — image SSRF + local-file read (`_fetch_image`, lines 231–249):**

```python def _fetch_image(src: Any) -> Image.Image: if isinstance(src, Image.Image): return _to_rgb(src) if isinstance(src, bytes): return _to_rgb(copy.deepcopy(Image.open(BytesIO(src)))) if isinstance(src, str): if src.startswith(("http://", "https://")): r = requests.get(src, timeout=30) # SSRF: no allowlist, follows redirects r.raise_for_status() return _to_rgb(copy.deepcopy(Image.open(BytesIO(r.content)))) if src.startswith("file://"): return _to_rgb(Image.open(src[7:])) # arbitrary local file read if src.startswith("data:image"): ... return _to_rgb(Image.open(src)) # fallback also opens local files raise ValueError(f"Unrecognized image source: {type(src)}") ```

**Sink 2 — audio SSRF (around line 471):**

```python elif audio.startswith(("http://", "https://")): r = requests.get(audio, timeout=30) # SSRF: same pattern r.raise_for_status() file_obj = io.BytesIO(r.content) ```

**Reachability.** `_fetch_image` is invoked from `MiMoVLProcessor.process_image`:

```python def process_image(self, image: ImageInput) -> torch.Tensor: kw = self._resolve_img_kw(image) src = image.image if isinstance(src, (str, bytes)): src = _fetch_image(src) ... ```

`MiMoVLProcessor` is wrapped by `MiMoV2OmniMultiModalProcessor` and registered for the `MiMoV2OmniForCausalLM` model architecture (`vllm/model_executor/models/mimo_v2_omni.py:1169`). Whenever a user passes a string into `multi_modal_data["image"]` (or `["audio"]`) for this model, the unsanitized URL/path reaches the sink.

**Comparison to the recent fixes.** The remediation pattern adopted in the three earlier advisories was to route every external resource fetch through `MediaConnector`, which checks `allowed_local_media_path` and applies SSRF protection before issuing the network request. `chat_utils.py` (lines 838, 902, 924, 963, 1053, 1081) already uses `self._connector.fetch_image / fetch_audio / fetch_video`. The model processor in `mimo_v2_omni.py` was added later and skipped the connector — it calls `requests.get` and `Image.open` directly. Result: the public OpenAI chat-completion path is protected, but library use (`LLM.generate(multi_modal_data=...)`), batch processing, and any other path that lets a string reach the processor receive no protection.

### Impact

1. **SSRF — internal-network probing / cloud-metadata theft.** Standard `requests.get` follows redirects and accepts any URL. An attacker who controls a `multi_modal_data` value can: - read AWS / GCP / Azure instance metadata (e.g. `http://169.254.169.254/latest/meta-data/iam/security-credentials/`), - probe internal services on the vLLM host (`http://127.0.0.1:<port>`, `http://10.x.y.z`), - exfiltrate via DNS / HTTP timing oracles even when the body is rejected by `Image.open`. 2. **Arbitrary local file read** via `file://path` (line 242) and the unguarded fallback `Image.open(src)` (line 248). Any file readable by the vLLM process is reachable through the model pipeline; with suitable formats this exposes `/etc/passwd`, `~/.aws/credentials`, etc. 3. **Server-side traffic generation / amplification** by hammering arbitrary URLs from the vLLM host, with a 30-second timeout per request.

### Suggested remediation

Replace direct `requests.get` and bare `Image.open` paths with `MediaConnector.fetch_image` / `fetch_audio_async` (or pass the inputs through `MediaConnector` before they reach the processor):

```python # vllm/transformers_utils/processors/mimo_v2_omni.py from vllm.multimodal.utils import MediaConnector

_connector = MediaConnector()

def _fetch_image(src): if isinstance(src, Image.Image): return _to_rgb(src) if isinstance(src, bytes): return _to_rgb(copy.deepcopy(Image.open(BytesIO(src)))) if isinstance(src, str): return _to_rgb(_connector.fetch_image(src)) # delegates to the hardened path raise ValueError(f"Unrecognized image source: {type(src)}") ```

Same change for the audio loader at line 471. This re-uses the SSRF allowlist, `allowed_local_media_path` policy, and size caps that the previous patches added.

Alternative: forbid `str` `src` from reaching the processor and require all multi-modal pre-processing to go through `chat_utils.py` / `MediaConnector` before hitting the model. Larger surface change, but completes the architectural fix.

### Discovery

Static review on `vllm@main` (HEAD as of 2026-04-30) — found by triaging the file list against the three recent SSRF advisories: the `mimo_v2_omni.py` processor, added after those fixes, reintroduced the same bypass class.

### Reporter

Ievgen Bondarenko — `sactransport2000@gmail.com` — GitHub `@ibondarenko1`