{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "vllm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.7.0"
            },
            {
              "fixed": "0.19.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34755"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-03T21:51:35Z",
    "nvd_published_at": "2026-04-06T16:16:36Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThe `VideoMediaIO.load_base64()` method at `vllm/multimodal/media/video.py:51-62` splits `video/jpeg` data URLs by comma to extract individual JPEG frames, but does not enforce a frame count limit. The `num_frames` parameter (default: 32), which is enforced by the `load_bytes()` code path at line 47-48, is completely bypassed in the `video/jpeg` base64 path. An attacker can send a single API request containing thousands of comma-separated base64-encoded JPEG frames, causing the server to decode all frames into memory and crash with OOM.\n\n## Details\n\n### Vulnerable code\n\n```python\n# video.py:51-62\ndef load_base64(self, media_type: str, data: str) -\u003e tuple[npt.NDArray, dict[str, Any]]:\n    if media_type.lower() == \"video/jpeg\":\n        load_frame = partial(self.image_io.load_base64, \"image/jpeg\")\n        return np.stack(\n            [np.asarray(load_frame(frame_data)) for frame_data in data.split(\",\")]\n            #                                                       ^^^^^^^^^^\n            # Unbounded split \u2014 no frame count limit\n        ), {}\n    return self.load_bytes(base64.b64decode(data))\n```\n\nThe `load_bytes()` path (line 47-48) properly delegates to a video loader that respects `self.num_frames` (default 32). The `load_base64(\"video/jpeg\", ...)` path bypasses this limit entirely \u2014 `data.split(\",\")` produces an unbounded list and every frame is decoded into a numpy array.\n\n### video/jpeg is part of vLLM\u0027s public API\n\n`video/jpeg` is a vLLM-specific MIME type, not IANA-registered. However it is part of the public API surface:\n\n- `encode_video_url()` at `vllm/multimodal/utils.py:96-108` generates `data:video/jpeg;base64,...` URLs\n- Official test suites at `tests/entrypoints/openai/test_video.py:62` and `tests/entrypoints/test_chat_utils.py:153` both use this format\n\n### Memory amplification\n\nEach JPEG frame decodes to a full numpy array. For 640x480 RGB images, each frame is ~921 KB decoded. 5000 frames = ~4.6 GB. `np.stack()` then creates an additional copy. The compressed JPEG payload is small (~100 KB for 5000 frames) but decompresses to gigabytes.\n\n### Data flow\n\n```\nPOST /v1/chat/completions\n  \u2192 chat_utils.py:1434   video_url type \u2192 mm_parser.parse_video()\n  \u2192 chat_utils.py:872    parse_video() \u2192 self._connector.fetch_video()\n  \u2192 connector.py:295     fetch_video() \u2192 load_from_url(url, self.video_io)\n  \u2192 connector.py:91      _load_data_url(): url_spec.path.split(\",\", 1)\n                          \u2192 media_type = \"video/jpeg\"\n                          \u2192 data = \"\u003cframe1\u003e,\u003cframe2\u003e,...,\u003cframe10000\u003e\"\n  \u2192 connector.py:100     media_io.load_base64(\"video/jpeg\", data)\n  \u2192 video.py:54          data.split(\",\")  \u2190 UNBOUNDED\n  \u2192 video.py:55-57       all frames decoded into numpy arrays\n  \u2192 video.py:56          np.stack([...])  \u2190 massive combined array \u2192 OOM\n```\n\n`connector.py:91` uses `split(\",\", 1)` which splits on only the first comma. All remaining commas stay in `data` and are later split by `video.py:54`.\n\n### Comparison with existing protections\n\n| Code Path | Frame Limit | File |\n|-----------|-------------|------|\n| `load_bytes()` (binary video) | Yes \u2014 `num_frames` (default 32) | video.py:46-49 |\n| `load_base64(\"video/jpeg\", ...)` | No \u2014 unlimited `data.split(\",\")` | video.py:51-62 |",
  "id": "GHSA-pq5c-rjhq-qp7p",
  "modified": "2026-04-06T23:20:56Z",
  "published": "2026-04-03T21:51:35Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/security/advisories/GHSA-pq5c-rjhq-qp7p"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34755"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/pull/38636"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vllm-project/vllm/commit/58ee61422169ce17e08248f8efa1e9df434fe395"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vllm-project/vllm"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "vLLM: Denial of Service via Unbounded Frame Count in video/jpeg Base64 Processing"
}