MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's JSON conversion helpers contain multiple recursion paths that do not consistently enforce a depth limit. These paths are in the JSON conversion component rather than normal typed MessagePack deserialization. MessagePackSerializer.ConvertFromJson recursively processes nested JSON arrays and objects in FromJsonCore() without consulting MessagePackSecurity.MaximumObjectGraphDepth. TinyJsonReader.ReadNextToken() recursively consumes comma and colon separator characters, allowing even malformed JSON with long separator runs to consume one stack frame per character. MessagePackSerializer.ConvertToJson applies depth checks to arrays and maps, but the typeless extension branch for ext-100 recursively calls ToJsonCore() without applying MessagePackSecurity.DepthStep(ref reader). Each path can allow attacker-controlled input to exhaust the process stack and trigger an uncatchable StackOverflowException instead of failing with a catchable parse or serialization exception. This vulnerability is fixed in 2.5.301 and 3.1.7.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-cj9g-3mj2-g8vv | MessagePack-CSharp: JSON conversion APIs can recurse without consistent depth enforcement |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 24 Jun 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Messagepack
Messagepack messagepack-csharp |
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| Vendors & Products |
Messagepack
Messagepack messagepack-csharp |
Tue, 23 Jun 2026 15:30:00 +0000
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| Metrics |
ssvc
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Mon, 22 Jun 2026 22:00:00 +0000
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| Description | MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePack-CSharp's JSON conversion helpers contain multiple recursion paths that do not consistently enforce a depth limit. These paths are in the JSON conversion component rather than normal typed MessagePack deserialization. MessagePackSerializer.ConvertFromJson recursively processes nested JSON arrays and objects in FromJsonCore() without consulting MessagePackSecurity.MaximumObjectGraphDepth. TinyJsonReader.ReadNextToken() recursively consumes comma and colon separator characters, allowing even malformed JSON with long separator runs to consume one stack frame per character. MessagePackSerializer.ConvertToJson applies depth checks to arrays and maps, but the typeless extension branch for ext-100 recursively calls ToJsonCore() without applying MessagePackSecurity.DepthStep(ref reader). Each path can allow attacker-controlled input to exhaust the process stack and trigger an uncatchable StackOverflowException instead of failing with a catchable parse or serialization exception. This vulnerability is fixed in 2.5.301 and 3.1.7. | |
| Title | MessagePack-CSharp: JSON conversion APIs can recurse without consistent depth enforcement | |
| Weaknesses | CWE-674 | |
| References |
| |
| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-06-25T15:16:38.766Z
Reserved: 2026-05-21T16:18:10.618Z
Link: CVE-2026-48512
Updated: 2026-06-23T14:56:55.700Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-06-24T16:07:20Z
Weaknesses
Github GHSA