CVE-2026-48502 (GCVE-0-2026-48502)
Vulnerability from cvelistv5 – Published: 2026-06-22 21:18 – Updated: 2026-06-22 21:18
VLAI
Title
MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows
Summary
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.
Severity
CWE
- CWE-125 - Out-of-bounds Read
- CWE-190 - Integer Overflow or Wraparound
- CWE-407 - Inefficient Algorithmic Complexity
- CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
- CWE-470 - Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
- CWE-502 - Deserialization of Untrusted Data
- CWE-674 - Uncontrolled Recursion
- CWE-789 - Memory Allocation with Excessive Size Value
- CWE-1188 - Insecure Default Initialization of Resource
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/MessagePack-CSharp/MessagePack… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| MessagePack-CSharp | MessagePack-CSharp |
Affected:
>= 3.1.7, < 3.1.7
Affected: < 2.5.301 |
{
"containers": {
"cna": {
"affected": [
{
"product": "MessagePack-CSharp",
"vendor": "MessagePack-CSharp",
"versions": [
{
"status": "affected",
"version": "\u003e= 3.1.7, \u003c 3.1.7"
},
{
"status": "affected",
"version": "\u003c 2.5.301"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "HIGH",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 8.2,
"baseSeverity": "HIGH",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-125",
"description": "CWE-125: Out-of-bounds Read",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-190",
"description": "CWE-190: Integer Overflow or Wraparound",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-407",
"description": "CWE-407: Inefficient Algorithmic Complexity",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-409",
"description": "CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-470",
"description": "CWE-470: Use of Externally-Controlled Input to Select Classes or Code (\u0027Unsafe Reflection\u0027)",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-502",
"description": "CWE-502: Deserialization of Untrusted Data",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-674",
"description": "CWE-674: Uncontrolled Recursion",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-789",
"description": "CWE-789: Memory Allocation with Excessive Size Value",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-1188",
"description": "CWE-1188: Insecure Default Initialization of Resource",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-22T21:18:29.190Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-382j-8mxh-c7x2",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-382j-8mxh-c7x2"
}
],
"source": {
"advisory": "GHSA-382j-8mxh-c7x2",
"discovery": "UNKNOWN"
},
"title": "MessagePack-CSharp: Denial of service vulnerabilities can swamp the CPU or crash the process with stack and heap overflows"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-48502",
"datePublished": "2026-06-22T21:18:29.190Z",
"dateReserved": "2026-05-21T15:33:08.293Z",
"dateUpdated": "2026-06-22T21:18:29.190Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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