MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePackReader.ReadDateTime() can allocate stack memory based on an attacker-controlled MessagePack extension length. In the slow path for timestamp extension parsing, the computed tokenSize includes the extension body length from the wire and is used in a stackalloc operation before the extension length is validated as one of the valid timestamp sizes. A very small payload can claim a large timestamp extension body and cause a stack allocation large enough to trigger an uncatchable StackOverflowException, terminating the host process. This vulnerability is fixed in 2.5.301 and 3.1.7.
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Mon, 22 Jun 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
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| Description | MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePackReader.ReadDateTime() can allocate stack memory based on an attacker-controlled MessagePack extension length. In the slow path for timestamp extension parsing, the computed tokenSize includes the extension body length from the wire and is used in a stackalloc operation before the extension length is validated as one of the valid timestamp sizes. A very small payload can claim a large timestamp extension body and cause a stack allocation large enough to trigger an uncatchable StackOverflowException, terminating the host process. This vulnerability is fixed in 2.5.301 and 3.1.7. | |
| Title | MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows | |
| Weaknesses | CWE-1188 CWE-125 CWE-190 CWE-407 CWE-409 CWE-470 CWE-502 CWE-674 CWE-789 |
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cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-06-22T21:18:29.190Z
Reserved: 2026-05-21T15:33:08.293Z
Link: CVE-2026-48502
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OpenCVE Enrichment
Updated: 2026-06-22T23:30:05Z