CVE-2026-54512— jackson-databind: PolymorphicTypeValidator bypass via generic type parameters allows arbitrary class instantiation

jackson-databind: PolymorphicTypeValidator bypass via generic type parameters allows arbitrary class instantiation

jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.10.0 until 2.18.8, 2.21.4, and 3.1.4, jackson-databind's PolymorphicTypeValidator (PTV) is the primary safety mechanism guarding polymorphic deserialization. When polymorphic typing is enabled and a type identifier contains generic parameters (i.e. the type ID string contains <), DatabindContext._resolveAndValidateGeneric() validates only the raw container class name (the substring before <) against the configured PTV. If the container type is approved, the method parses the full canonical type string via TypeFactory.constructFromCanonical() and returns the fully parameterized type without ever validating the nested type arguments against the PTV. The nested type arguments are then resolved, instantiated, and populated as beans during deserialization. An attacker who controls the type ID can therefore place a denied class as a generic type parameter of an allowed container — for example java.util.ArrayList<com.evil.Gadget> when only java.util.ArrayList is allow-listed. The container passes the PTV check; com.evil.Gadget is loaded via Class.forName(name, true, loader), instantiated, and its properties are set from attacker-controlled JSON. This completely bypasses an explicitly configured PTV allow-list. This vulnerability is fixed in 2.18.8, 2.21.4, and 3.1.4.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

不完整的黑名单

FasterXML jackson-databind 输入验证错误漏洞

FasterXML jackson-databind是FasterXML组织开源的其中的一个具有数据绑定功能的组件。 FasterXML jackson-databind 2.10.0版本至2.18.8之前版本、2.19.0版本至2.21.4之前版本和3.0.0版本至3.1.4之前版本存在安全漏洞，该漏洞源于PolymorphicTypeValidator验证不完整，当多态类型启用且类型标识符包含泛型参数时，仅验证容器类名而未验证嵌套类型参数，可通过特制类型ID绕过PTV白名单，导致反序列化时加载并实例化

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