vLLM’s Chunk-Based Prefix Caching Vulnerable to Potential Timing Side-Channel

{
  "id": "a677ab33831cafb719aca61b63bc51df2b7dfaa05fde8e104c2b6274e04b8b03",
  "url": "https://osv.dev/vulnerability/CVE-2025-46570",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vLLM’s Chunk-Based Prefix Caching Vulnerable to Potential Timing Side-Channel",
    "summary": "vLLM is an inference and serving engine for large language models (LLMs). Prior to version 0.9.0, when a new prompt is processed, if the PageAttention mechanism finds a matching prefix chunk, the prefill process speeds up, which is reflected in the TTFT (Time to First Token). These timing differences caused by matching chunks are significant enough to be recognized and exploited. This issue has been patched in version 0.9.0.",
    "evidence": "osv:CVE-2025-46570",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2025-46570",
      "aliases": [
        "CVE-2025-46570",
        "GHSA-4qjh-9fv9-r85r",
        "PYSEC-2025-53"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/vllm-project/vllm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "58738772410c5e0d60b61db39538a9b313d2d7ad"
                },
                {
                  "fixed": "77073c77bc2006eb80ea6d5128f076f5e6c6f54f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.9.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "77073c77bc2006eb80ea6d5128f076f5e6c6f54f"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.8.4",
            "v0.8.3rc1",
            "v0.8.2",
            "v0.8.1",
            "v0.8.0rc2",
            "v0.8.0rc1",
            "v0.7.3",
            "v0.7.2",
            "v0.7.1",
            "v0.7.0",
            "v0.6.6.post1",
            "v0.6.6",
            "v0.6.5",
            "v0.6.4.post1",
            "v0.6.4",
            "v0.6.3.post1",
            "v0.6.3",
            "v0.6.2",
            "v0.6.1.post2",
            "v0.6.1.post1",
            "v0.6.1",
            "v0.6.0",
            "v0.5.5",
            "v0.5.4",
            "v0.5.3.post1",
            "v0.5.3",
            "v0.5.2",
            "v0.5.1",
            "v0.5.0.post1",
            "v0.5.0",
            "v0.4.3",
            "v0.4.2",
            "v0.4.1",
            "v0.4.0.post1",
            "v0.4.0",
            "v0.3.3",
            "v0.3.2",
            "v0.3.1",
            "v0.3.0",
            "v0.2.7",
            "v0.2.6",
            "v0.2.5",
            "v0.2.4",
            "v0.2.3",
            "v0.2.2",
            "v0.2.1",
            "v0.2.0",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1.0",
            "submission"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-46570.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.598070941Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/46xxx/CVE-2025-46570.json",
        "https://github.com/vllm-project/vllm/security/advisories/GHSA-4qjh-9fv9-r85r",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-46570",
        "https://github.com/vllm-project/vllm/commit/77073c77bc2006eb80ea6d5128f076f5e6c6f54f",
        "https://github.com/vllm-project/vllm/pull/17045"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-208"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/46xxx/CVE-2025-46570.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-46570",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497514,
  "published_at": "2025-05-29T16:32:42.794+00:00"
}