{"id":"CVE-2026-92707","revision":"a3d405e2561f49a5b90a4dd44b3e8a97","records":[{"revision":"a3d405e2561f49a5b90a4dd44b3e8a97","observedAt":"2026-10-25T16:19:22.228+00:00","statement":{"source":"nvd","id":"CVE-2026-92707","aliases":[],"title":"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 all…","description":"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.","state":0,"publishedAt":"2026-10-15T19:17:48.703+00:00","modifiedAt":"2026-10-16T16:00:33.533+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3,"severity":"MEDIUM"}],"references":["https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a","https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c","https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303","https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9","https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-92707","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Awaiting Analysis","weaknesses":["CWE-1325"],"productCriteria":[],"sourceDates":{"published":"2026-10-15T19:17:48.703","lastModified":"2026-10-16T16:00:33.533"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-92707","identifiers":["CVE-2026-92707"]},"retained":false,"historicalAffected":[]}],"coverage":[]}