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CVE-2026-48516

MEDIUM
6.3
CVSS 4.0
Description
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, InterfaceLookupFormatter<TKey,TElement> constructs an internal Dictionary<TKey, IGrouping<TKey,TElement>> with the default equality comparer instead of the security-aware comparer supplied by options.Security.GetEqualityComparer<TKey>(). This formatter omission allows hash-collision CPU denial of service against ILookup<TKey,TElement> even when the application has opted into the untrusted-data security posture This vulnerability is fixed in 2.5.301 and 3.1.7.

Metadata

CVE ID
CVE-2026-48516
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-05-21 16:18 UTC
Published
2026-06-22 21:09 UTC
Last updated
2026-06-22 21:09 UTC
Primary CWE
CWE-407
CWE-407: Inefficient Algorithmic Complexity
Vendor / Product
MessagePack-CSharp / MessagePack-CSharp
Sources
cve.org  ·  NVD

Severity & Metrics

6.3 MEDIUM CVSS 4.0
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Affected products (1)
VendorProductPlatformVersions
MessagePack-CSharp MessagePack-CSharp — >= 3.1.7, < 3.1.7, < 2.5.301
Weakness (CWE)
CWESourceDescription
CWE-407 cna CWE-407: Inefficient Algorithmic Complexity
CVSS scores (1)
ScoreSeverityVersionSourceVector
6.3 MEDIUM 4.0 cna CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
References (1)
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