vLLM phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service

{
  "id": "4c104632a722982081dbe02444c47cbefed5b0ba4847b7e766f4ac43f9f5dc1d",
  "url": "https://osv.dev/vulnerability/CVE-2025-46560",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vLLM phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service",
    "summary": "vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Versions starting from 0.8.0 and prior to 0.8.5 are affected by a critical performance vulnerability in the input preprocessing logic of the multimodal tokenizer. The code dynamically replaces placeholder tokens (e.g., <|audio_|>, <|image_|>) with repeated tokens based on precomputed lengths. Due to ​​inefficient list concatenation operations​​, the algorithm exhibits ​​quadratic time complexity (O(n²))​​, allowing malicious actors to trigger resource exhaustion via specially crafted inputs. This issue has been patched in version 0.8.5.",
    "evidence": "osv:CVE-2025-46560",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-46560",
      "aliases": [
        "CVE-2025-46560",
        "GHSA-vc6m-hm49-g9qg",
        "PYSEC-2026-2022"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/vllm-project/vllm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "966f933ee1cd7c9a41db60de5c7ff98657005251"
                },
                {
                  "fixed": "ba41cc90e8ef7f236347b2f1599eec2cbb9e1f0d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.8.0"
                      },
                      {
                        "fixed": "0.8.5"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.8.0"
                      },
                      {
                        "fixed": "0.8.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-46560.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.308932545Z",
      "provider": "osv",
      "references": [
        "https://github.com/vllm-project/vllm/blob/8cac35ba435906fb7eb07e44fe1a8c26e8744f4e/vllm/model_executor/models/phi4mm.py#L1182-L1197",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/46xxx/CVE-2025-46560.json",
        "https://github.com/vllm-project/vllm/security/advisories/GHSA-vc6m-hm49-g9qg",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-46560"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1333"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/46xxx/CVE-2025-46560.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-46560",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510866,
  "published_at": "2025-04-30T00:24:53.75+00:00"
}