PT-2026-51395 · Messagepack Csharp · Messagepack-Csharp

Publicado 2026-06-22 · Atualizado 2026-06-22 · CVE-2026-48511

Mitre

CVSS v4.0

6.3

Média

Vetor base

AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, ExpandoObjectFormatter.Deserialize populates System.Dynamic.ExpandoObject by calling IDictionary<string, object>.Add for each map entry. ExpandoObject internally maintains member names in array-like structures, so inserting many distinct keys can require repeated linear scans and array copies. For large attacker-controlled maps, this produces quadratic CPU and allocation behavior. The issue is especially surprising because ExpandoObjectResolver.Options is configured with MessagePackSecurity.UntrustedData, but collision-resistant dictionary comparers cannot protect ExpandoObject insertion internals. This vulnerability is fixed in 2.5.301 and 3.1.7.

Correção

Enumeração de Fraquezas

CWE-407

Identificadores relacionados

CVE-2026-48511

Produtos afetados

Messagepack-Csharp

Referências · 2

• https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-2x83-8g95-xh59 · Nota
• https://nvd.nist.gov/vuln/detail/CVE-2026-48511 · Nota de Segurança