Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the BeanDeserializerBase.createContextual() method, which applies the per-property exclusions through _handleByNameInclusion() and then rebuilds the property map from the unfiltered original, overwriting the filtered map and restoring every property the exclusion had removed. An attacker can set fields that were marked ignored, enabling mass assignment, by supplying those property names in untrusted JSON during deserialization. Exploitation requires case-insensitive property matching to be enabled via @JsonFormat with ACCEPT_CASE_INSENSITIVE_PROPERTIES alongside per-property @JsonIgnoreProperties.
Remediation
A fix was pushed into the master branch but not yet published.