CVEDB API

Vulnerabilities

Vulnerable Software

Vulnerability Details 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<string, object>.Add for each map entry. ExpandoObject internally maintains member names in array-like structures, so inserting many distinct keys can require repeated linear scans and array copies. For large attacker-controlled maps, this produces quadratic CPU and allocation behavior. The issue is especially surprising because ExpandoObjectResolver.Options is configured with MessagePackSecurity.UntrustedData, but collision-resistant dictionary comparers cannot protect ExpandoObject insertion internals. This vulnerability is fixed in 2.5.301 and 3.1.7.

Exploit prediction scoring system (EPSS) score

EPSS Score 0.002

EPSS Ranking 10.8%

CVSS Severity

CVSS v3 Score 7.5

References

https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-2x83-8g95-xh59

Products affected by CVE-2026-48511

Messagepack » Messagepack » Version: .1.7.3.5

cpe:2.3:a:messagepack:messagepack:.1.7.3.5
Messagepack » Messagepack » Version: .1.7.3.6

cpe:2.3:a:messagepack:messagepack:.1.7.3.6
Messagepack » Messagepack » Version: 1.0.1

cpe:2.3:a:messagepack:messagepack:1.0.1
Messagepack » Messagepack » Version: 1.0.2

cpe:2.3:a:messagepack:messagepack:1.0.2
Messagepack » Messagepack » Version: 1.0.3

cpe:2.3:a:messagepack:messagepack:1.0.3
Messagepack » Messagepack » Version: 1.1.0

cpe:2.3:a:messagepack:messagepack:1.1.0
Messagepack » Messagepack » Version: 1.1.1

cpe:2.3:a:messagepack:messagepack:1.1.1
Messagepack » Messagepack » Version: 1.1.2

cpe:2.3:a:messagepack:messagepack:1.1.2
Messagepack » Messagepack » Version: 1.2.0

cpe:2.3:a:messagepack:messagepack:1.2.0
Messagepack » Messagepack » Version: 1.2.1

cpe:2.3:a:messagepack:messagepack:1.2.1
Messagepack » Messagepack » Version: 1.2.3

cpe:2.3:a:messagepack:messagepack:1.2.3
Messagepack » Messagepack » Version: 1.3.0

cpe:2.3:a:messagepack:messagepack:1.3.0
Messagepack » Messagepack » Version: 1.3.1

cpe:2.3:a:messagepack:messagepack:1.3.1
Messagepack » Messagepack » Version: 1.3.2

cpe:2.3:a:messagepack:messagepack:1.3.2
Messagepack » Messagepack » Version: 1.3.3

cpe:2.3:a:messagepack:messagepack:1.3.3
Messagepack » Messagepack » Version: 1.4.0

cpe:2.3:a:messagepack:messagepack:1.4.0
Messagepack » Messagepack » Version: 1.4.1

cpe:2.3:a:messagepack:messagepack:1.4.1
Messagepack » Messagepack » Version: 1.4.2

cpe:2.3:a:messagepack:messagepack:1.4.2
Messagepack » Messagepack » Version: 1.4.3

cpe:2.3:a:messagepack:messagepack:1.4.3
Messagepack » Messagepack » Version: 1.4.4

cpe:2.3:a:messagepack:messagepack:1.4.4
Messagepack » Messagepack » Version: 1.5.0

cpe:2.3:a:messagepack:messagepack:1.5.0
Messagepack » Messagepack » Version: 1.5.1

cpe:2.3:a:messagepack:messagepack:1.5.1
Messagepack » Messagepack » Version: 1.6.0

cpe:2.3:a:messagepack:messagepack:1.6.0
Messagepack » Messagepack » Version: 1.6.1

cpe:2.3:a:messagepack:messagepack:1.6.1
Messagepack » Messagepack » Version: 1.6.1.2

cpe:2.3:a:messagepack:messagepack:1.6.1.2
Messagepack » Messagepack » Version: 1.6.2

cpe:2.3:a:messagepack:messagepack:1.6.2
Messagepack » Messagepack » Version: 1.7.0

cpe:2.3:a:messagepack:messagepack:1.7.0
Messagepack » Messagepack » Version: 1.7.1

cpe:2.3:a:messagepack:messagepack:1.7.1
Messagepack » Messagepack » Version: 1.7.2

cpe:2.3:a:messagepack:messagepack:1.7.2
Messagepack » Messagepack » Version: 1.7.3

cpe:2.3:a:messagepack:messagepack:1.7.3
Messagepack » Messagepack » Version: 1.7.3.1

cpe:2.3:a:messagepack:messagepack:1.7.3.1
Messagepack » Messagepack » Version: 1.7.3.2

cpe:2.3:a:messagepack:messagepack:1.7.3.2
Messagepack » Messagepack » Version: 1.7.3.3

cpe:2.3:a:messagepack:messagepack:1.7.3.3
Messagepack » Messagepack » Version: 1.7.3.4

cpe:2.3:a:messagepack:messagepack:1.7.3.4
Messagepack » Messagepack » Version: 1.7.3.7

cpe:2.3:a:messagepack:messagepack:1.7.3.7
Messagepack » Messagepack » Version: 1.9.3

cpe:2.3:a:messagepack:messagepack:1.9.3
Messagepack » Messagepack » Version: 2.0.110

cpe:2.3:a:messagepack:messagepack:2.0.110
Messagepack » Messagepack » Version: 2.0.119

cpe:2.3:a:messagepack:messagepack:2.0.119
Messagepack » Messagepack » Version: 2.0.123

cpe:2.3:a:messagepack:messagepack:2.0.123
Messagepack » Messagepack » Version: 2.0.204

cpe:2.3:a:messagepack:messagepack:2.0.204
Messagepack » Messagepack » Version: 2.0.270

cpe:2.3:a:messagepack:messagepack:2.0.270
Messagepack » Messagepack » Version: 2.0.299

cpe:2.3:a:messagepack:messagepack:2.0.299
Messagepack » Messagepack » Version: 2.0.323

cpe:2.3:a:messagepack:messagepack:2.0.323
Messagepack » Messagepack » Version: 2.0.335

cpe:2.3:a:messagepack:messagepack:2.0.335
Messagepack » Messagepack » Version: 2.0.94

cpe:2.3:a:messagepack:messagepack:2.0.94
Messagepack » Messagepack » Version: 2.1.115

cpe:2.3:a:messagepack:messagepack:2.1.115
Messagepack » Messagepack » Version: 2.1.143

cpe:2.3:a:messagepack:messagepack:2.1.143
Messagepack » Messagepack » Version: 2.1.152

cpe:2.3:a:messagepack:messagepack:2.1.152
Messagepack » Messagepack » Version: 2.1.165

cpe:2.3:a:messagepack:messagepack:2.1.165
Messagepack » Messagepack » Version: 2.1.194

cpe:2.3:a:messagepack:messagepack:2.1.194
Messagepack » Messagepack » Version: 2.1.80

cpe:2.3:a:messagepack:messagepack:2.1.80
Messagepack » Messagepack » Version: 2.1.90

cpe:2.3:a:messagepack:messagepack:2.1.90
Messagepack » Messagepack » Version: 2.2.113

cpe:2.3:a:messagepack:messagepack:2.2.113
Messagepack » Messagepack » Version: 2.2.36

cpe:2.3:a:messagepack:messagepack:2.2.36
Messagepack » Messagepack » Version: 2.2.44

cpe:2.3:a:messagepack:messagepack:2.2.44
Messagepack » Messagepack » Version: 2.2.60

cpe:2.3:a:messagepack:messagepack:2.2.60
Messagepack » Messagepack » Version: 2.2.85

cpe:2.3:a:messagepack:messagepack:2.2.85
Messagepack » Messagepack » Version: 2.3.112

cpe:2.3:a:messagepack:messagepack:2.3.112
Messagepack » Messagepack » Version: 2.3.58

cpe:2.3:a:messagepack:messagepack:2.3.58
Messagepack » Messagepack » Version: 2.3.73

cpe:2.3:a:messagepack:messagepack:2.3.73
Messagepack » Messagepack » Version: 2.3.75

cpe:2.3:a:messagepack:messagepack:2.3.75
Messagepack » Messagepack » Version: 2.3.85

cpe:2.3:a:messagepack:messagepack:2.3.85
Messagepack » Messagepack » Version: 2.4.14

cpe:2.3:a:messagepack:messagepack:2.4.14
Messagepack » Messagepack » Version: 2.4.23

cpe:2.3:a:messagepack:messagepack:2.4.23
Messagepack » Messagepack » Version: 2.4.35

cpe:2.3:a:messagepack:messagepack:2.4.35
Messagepack » Messagepack » Version: 2.4.59

cpe:2.3:a:messagepack:messagepack:2.4.59
Messagepack » Messagepack » Version: 2.5.103

cpe:2.3:a:messagepack:messagepack:2.5.103
Messagepack » Messagepack » Version: 2.5.108

cpe:2.3:a:messagepack:messagepack:2.5.108
Messagepack » Messagepack » Version: 2.5.124

cpe:2.3:a:messagepack:messagepack:2.5.124
Messagepack » Messagepack » Version: 2.5.129

cpe:2.3:a:messagepack:messagepack:2.5.129
Messagepack » Messagepack » Version: 2.5.140

cpe:2.3:a:messagepack:messagepack:2.5.140
Messagepack » Messagepack » Version: 2.5.168

cpe:2.3:a:messagepack:messagepack:2.5.168
Messagepack » Messagepack » Version: 2.5.171

cpe:2.3:a:messagepack:messagepack:2.5.171
Messagepack » Messagepack » Version: 2.5.172

cpe:2.3:a:messagepack:messagepack:2.5.172
Messagepack » Messagepack » Version: 2.5.187

cpe:2.3:a:messagepack:messagepack:2.5.187
Messagepack » Messagepack » Version: 2.5.192

cpe:2.3:a:messagepack:messagepack:2.5.192
Messagepack » Messagepack » Version: 2.5.198

cpe:2.3:a:messagepack:messagepack:2.5.198
Messagepack » Messagepack » Version: 2.5.205

cpe:2.3:a:messagepack:messagepack:2.5.205
Messagepack » Messagepack » Version: 2.5.64

cpe:2.3:a:messagepack:messagepack:2.5.64
Messagepack » Messagepack » Version: 2.5.94

cpe:2.3:a:messagepack:messagepack:2.5.94
Messagepack » Messagepack » Version: 3.0.111

cpe:2.3:a:messagepack:messagepack:3.0.111
Messagepack » Messagepack » Version: 3.0.129

cpe:2.3:a:messagepack:messagepack:3.0.129
Messagepack » Messagepack » Version: 3.0.134

cpe:2.3:a:messagepack:messagepack:3.0.134
Messagepack » Messagepack » Version: 3.0.208

cpe:2.3:a:messagepack:messagepack:3.0.208
Messagepack » Messagepack » Version: 3.0.214

cpe:2.3:a:messagepack:messagepack:3.0.214
Messagepack » Messagepack » Version: 3.0.233

cpe:2.3:a:messagepack:messagepack:3.0.233
Messagepack » Messagepack » Version: 3.0.238

cpe:2.3:a:messagepack:messagepack:3.0.238
Messagepack » Messagepack » Version: 3.0.3

cpe:2.3:a:messagepack:messagepack:3.0.3
Messagepack » Messagepack » Version: 3.0.300

cpe:2.3:a:messagepack:messagepack:3.0.300
Messagepack » Messagepack » Version: 3.0.301

cpe:2.3:a:messagepack:messagepack:3.0.301
Messagepack » Messagepack » Version: 3.0.54

cpe:2.3:a:messagepack:messagepack:3.0.54
Messagepack » Messagepack » Version: 3.1.0

cpe:2.3:a:messagepack:messagepack:3.1.0
Messagepack » Messagepack » Version: 3.1.1

cpe:2.3:a:messagepack:messagepack:3.1.1
Messagepack » Messagepack » Version: 3.1.2

cpe:2.3:a:messagepack:messagepack:3.1.2
Messagepack » Messagepack » Version: 3.1.3

cpe:2.3:a:messagepack:messagepack:3.1.3
Messagepack » Messagepack » Version: 3.1.4

cpe:2.3:a:messagepack:messagepack:3.1.4
Messagepack » Messagepack » Version: 3.1.5

cpe:2.3:a:messagepack:messagepack:3.1.5
Messagepack » Messagepack » Version: 3.1.6

cpe:2.3:a:messagepack:messagepack:3.1.6

Vulnerabilities

Vulnerable Software

Vulnerability Details CVE-2026-48511

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