CVE-2026-54513 – jackson-databind: Array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray)

CVE ID :CVE-2026-54513

Published : June 23, 2026, 8:53 p.m. | 50 minutes ago

Description :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.

Severity: 0.0 | NA

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