CVEvulnerability

CVE-2026-48509

6.3 MEDIUM Published 2026-06-22 Modified 2026-06-25 Official page ↗
Status
Analyzed
Published
2026-06-22
Last modified
2026-06-25
Assigner
[email protected]
CVSS 4.0 ([email protected])
6.3 MEDIUM — CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Weaknesses
CWE-1188

Description

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, the parameterless MessagePackInputFormatter() constructor uses default serializer options, which resolve to MessagePackSerializerOptions.Standard with MessagePackSecurity.TrustedData. The formatter is designed for ASP.NET Core MVC request bodies, which commonly cross an HTTP trust boundary. This insecure default can expose applications to denial-of-service attacks that MessagePackSecurity.UntrustedData is intended to mitigate, such as hash-collision attacks against dictionary-like model properties. This vulnerability is fixed in 2.5.301 and 3.1.7.

Affected configurations

• messagepack messagepack (< 2.5.301) • messagepack messagepack (>= 3.0.3 < 3.1.7)

Related

Weakness · CWE (1)

  • CWE-1188 Initialization of a Resource with an Insecure Default weakness

References