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CVE-2026-48513

MessagePack-CSharp: DynamicUnionResolver generated deserializers miss depth enforcement

Published: Jun 22, 2026Updated: Jun 25, 2026 Sources: CVE List NVDCWE-674
7.5HIGH
NVD MITRE
EPSS Score
0.4%
Top 66.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Workaround Only
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-674

Affected Products

MessagePack-CSharp
oss-projectaka messagepack c#
MessagePack-CSharpLibrary
OSS Libraries / nuget
messagepack
oss-projectaka messagepack.org
messagepackLibrary
OSS Libraries / crates-io

Exploitability

Workaround Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-wfr3-xj75-pfwh
github.com

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