EUVD-2026-38385

MessagePack-CSharp: ExpandoObject formatter can perform quadratic insertion work on untrusted maps...

CVE-2026-48511

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, ExpandoObjectFormatter.Deserialize populates System.Dynamic.ExpandoObject by calling IDictionary.Add for each map entry. ExpandoObject internally maintains member names in array-like structures, so inserting many...

CVE-2026-48511

Summary: CVE-2026-48511 affects MessagePack for C# where ExpandoObjectFormatter.Deserialize inserts map entries into ExpandoObject via IDictionary.Add. This insertion pattern, coupled with ExpandoObject’s internal array-like member storage, can trigger repeated linear scans and array copies, caus...

CVE-2026-48511 MessagePack-CSharp: ExpandoObject formatter can perform quadratic insertion work on untrusted maps

MessagePack for C is a MessagePack serializer for C. Prior to 2.5.301 and 3.1.7, ExpandoObjectFormatter.Deserialize populates System.Dynamic.ExpandoObject by calling IDictionary.Add for each map entry. ExpandoObject internally maintains member names in array-like structures, so inserting many...

PT-2026-51395

Name of the Vulnerable Software and Affected Versions MessagePack for C versions prior to 2.5.301 MessagePack for C versions prior to 3.1.7 Description The ExpandoObjectFormatter.Deserialize function populates System.Dynamic.ExpandoObject by calling IDictionary.Add for each map entry. Because...

GHSA-92VJ-HP7M-GWCJ Nerdbank.MessagePack has Inefficient CPU Computation

Impact Applications that call OptionalConverters.WithExpandoObjectConverter and deserialize untrusted data are open to a vulnerability by which an attacker can exploit a On² algorithm to burn an inordinate amount of CPU effort by adding a great many properties to an ExpandoObject, whose Add metho...

PT-2026-47560

Impact Applications that call OptionalConverters.WithExpandoObjectConverter and deserialize untrusted data are open to a vulnerability by which an attacker can exploit a On² algorithm to burn an inordinate amount of CPU effort by adding a great many properties to an ExpandoObject, whose Add metho...