CVE-2026-54513
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk48th percentile — higher than 48% of all known CVEs
Summary
A vulnerability in jackson-databind allows bypassing the allowlist in BasicPolymorphicTypeValidator. The allowIfSubTypeIsArray() method permits any array type without validating the component type, enabling deserialization of dangerous types like EvilType[] even if EvilType is not allowlisted.
Risk Assessment
An attacker can remotely perform unauthorized object deserialization, leading to remote code execution (RCE) or other deserialization attacks, posing a serious security risk to the application.
Recommendation
Immediately update jackson-databind to version 2.18.8, 2.21.4, or 3.1.4. If updating is not possible, avoid using allowIfSubTypeIsArray() in BasicPolymorphicTypeValidator configuration.
Original NVD description (English source)
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, BasicPolymorphicTypeValidator.Builder.allowIfSubTypeIsArray() allowlists any array type based only on clazz.isArray(), without validating the array's component (element) type against the configured allowlist. A PTV built with allowIfSubTypeIsArray() plus an explicit concrete-type allowlist therefore still permits EvilType[] even though EvilType is not allowlisted. When Jackson deserializes the elements and no per-element type IDs are present, it instantiates the component type directly with no further PTV check, bypassing the allowlist. This vulnerability is fixed in 2.18.8, 2.21.4, and 3.1.4.