{"id":"AZL-113045","summary":"CVE-2026-92707 affecting package python-msgpack 1.2.3-1","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.","modified":"2026-11-13T06:04:48Z","published":"2026-10-15T19:17:48Z","upstream":["CVE-2026-92707"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-92707"}],"affected":[{"package":{"name":"python-msgpack","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/python-msgpack"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.2.3-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-113045.json"}}],"schema_version":"1.9.2"}