{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.5.303"
              },
              {
                "introduced": "3.0.0"
              },
              {
                "fixed": "3.1.9"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7fd78bbf3476e03beae8b0f7a521125525a8a64a"
            },
            {
              "fixed": "aa16e71ae548645050f0a6798874540f3149681b"
            },
            {
              "fixed": "95b63fca4f7097d3cac12d1a95286af4b4bbf02c"
            }
          ],
          "repo": "https://github.com/messagepack-csharp/messagepack-csharp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qhrr-8q5h-9q3h"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1325"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/92xxx/CVE-2026-92707.json"
  },
  "details": "MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9.",
  "id": "CVE-2026-92707",
  "modified": "2026-10-17T02:30:55.523190545Z",
  "published": "2026-10-15T18:35:49.074Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/92xxx/CVE-2026-92707.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-92707"
    },
    {
      "type": "FIX",
      "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MessagePack: Nested arrays can blow past buffer length limits"
}