CVE-2026-54513
jackson-databind: Array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray)
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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.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-rmj7-2vxq-3g9f
- https://github.com/FasterXML/jackson-databind/issues/5983
- https://github.com/FasterXML/jackson-databind/pull/5984
- https://github.com/FasterXML/jackson-databind/commit/01d1692c8d0ed03e51a0e3c4f8a9e6908e4931e5
- https://github.com/FasterXML/jackson-databind/commit/24529da29fdf46ff94ca38de9ebf31cd188f5e8e
References (32)
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SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.
CVSS
- Attack Vector
- NETWORK
- Complexity
- HIGH
- Privileges
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- HIGH
- Integrity
- HIGH
- Availability
- HIGH
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