CVE-2026-48515

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's multi-dimensional array formatters read dimension lengths directly from the payload and allocate T[,], T[,,], or T[,,,] before validating that the dimension product matches the encoded element count. The formatter reads a guarded element array header, but allocation of the target multi-dimensional array happens before the dimensions are checked against that element count. A small payload can therefore declare large dimensions, provide an empty or tiny inner array, and cause a large heap allocation before element data is validated. 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-cxmj-83gh-fp49	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, 17:20

Type	Values Removed	Values Added
First Time		Messagepack messagepack Messagepack
CPE		cpe:2.3:a:messagepack:messagepack::::::c\#::*
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
References	~~() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-cxmj-83gh-fp49 -~~	() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-cxmj-83gh-fp49 - Mitigation, Vendor Advisory

22 Jun 2026, 22:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-22 22:16

Updated : 2026-06-25 17:16

NVD link : CVE-2026-48515

Mitre link : CVE-2026-48515

CVE.ORG link : CVE-2026-48515

JSON object : View

Products Affected

messagepack

messagepack

CWE

CWE-770

Allocation of Resources Without Limits or Throttling

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