CVE-2026-48513

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, runtime-generated union deserializers emitted by DynamicUnionResolver do not call MessagePackSecurity.DepthStep(ref reader) and do not decrement reader.Depth around recursive deserialization and skip paths. This means union deserialization does not consistently participate in the maximum object graph depth enforcement that protects other recursive formatter paths. For unknown union keys, the emitted deserializer calls reader.Skip() on attacker-controlled data without an enclosing depth step. This vulnerability is fixed in 2.5.301 and 3.1.7.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwh	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:messagepack:messagepack::::::c\#::*
	cpe:2.3:a:messagepack:messagepack::::::c\#::*

History

23 Jun 2026, 17:21

Type	Values Removed	Values Added
References	~~() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwh -~~	() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwh - Mitigation, Vendor Advisory
First Time		Messagepack messagepack Messagepack
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
CPE		cpe:2.3:a:messagepack:messagepack::::::c\#::*

22 Jun 2026, 22:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-22 22:16

Updated : 2026-06-25 16:16

NVD link : CVE-2026-48513

Mitre link : CVE-2026-48513

CVE.ORG link : CVE-2026-48513

JSON object : View

Products Affected

messagepack

messagepack

CWE

CWE-674

Uncontrolled Recursion

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