CVE-2026-48510

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large uncompressed length and force a large allocation before LZ4 decoding begins. 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-v72x-2h86-7f8m	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, 17:24

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
References	~~() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-v72x-2h86-7f8m -~~	() https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-v72x-2h86-7f8m - Mitigation, Vendor Advisory
First Time		Messagepack messagepack Messagepack
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-2026-48510

Mitre link : CVE-2026-48510

CVE.ORG link : CVE-2026-48510

JSON object : View

Products Affected

messagepack

messagepack

CWE

CWE-409

Improper Handling of Highly Compressed Data (Data Amplification)

CWE-770

Allocation of Resources Without Limits or Throttling

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