CVE-2026-92707 (GCVE-0-2026-92707)

Vulnerability from cvelistv5 – Published: 2026-10-15 18:35 – Updated: 2026-10-15 20:12
VLAI
Title
MessagePack: Nested arrays can blow past buffer length limits
Summary
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-15 20:10 UTC
CWE
  • CWE-1325 - Improperly Controlled Sequential Memory Allocation
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7861 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
MessagePack-CSharp MessagePack-CSharp Affected: < 2.5.303
Affected: >= 3.0.0, < 3.1.9
guessed Create a notification for this product.
Show details on NVD website
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