CVE-2026-48512

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:messagepack:messagepack:*:*:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:*:*:*:*:*:c\#:*:*

History

23 Jun 2026, 17:21

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 7.5
CPE cpe:2.3:a:messagepack:messagepack:*:*:*:*:*:c\#:*:*
First Time Messagepack messagepack
Messagepack
References () https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-cj9g-3mj2-g8vv - () https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-cj9g-3mj2-g8vv - 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 16:16


NVD link : CVE-2026-48512

Mitre link : CVE-2026-48512

CVE.ORG link : CVE-2026-48512


JSON object : View

Products Affected

messagepack

  • messagepack
CWE
CWE-674

Uncontrolled Recursion