---
id: CVE-2026-83557
title: >-
  DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied
  automatically whenever @JsonTypeInfo is used without an explicitly configured
  custom validator
summary: >-
  DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied
  automatically whenever @JsonTypeInfo is used without an explicitly configured
  custom validator. It denies polymorphic resolution only for a fixed set of
  "unsafe bas…
severity: medium
cvss: 5.6
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-502
  - CWE-915
  - CWE-1287
published: '2026-09-01'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T19:29:32.200'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-83557'
references:
  - url: >-
      https://github.com/FasterXML/jackson-databind/commit/eb3b7fc0f9c0d27f471550ac3316b17d1987388f
    label: 36c7be3b-2937-45df-85ea-ca7133ea542c
  - url: 'https://github.com/FasterXML/jackson-databind/issues/6156'
    label: 36c7be3b-2937-45df-85ea-ca7133ea542c
  - url: 'https://github.com/FasterXML/jackson-databind/pull/6155'
    label: 36c7be3b-2937-45df-85ea-ca7133ea542c
  - url: >-
      https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-gx83-3vf8-gh7j
    label: 36c7be3b-2937-45df-85ea-ca7133ea542c
  - url: >-
      https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-gx83-3vf8-gh7j
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-83557.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-83557'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2526847'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-83557'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-83557'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00711
epssPercentile: 0.51654
ingestedAt: '2026-09-08T20:10:03.159Z'
vendor: Red Hat
product: Red Hat Enterprise Linux 8
affected:
  - exploit_intelligence
  - openshift_developer_tools_and_services
  - openshift_serverless
  - ai_inference_server
  - amq_broker 7
  - ansible_automation_platform 2
  - build_of_apache_camel_4_for_quarkus 3
  - build_of_apache_camel_for_spring_boot 4
  - build_of_apicurio_registry 3
  - build_of_debezium 3
  - build_of_keycloak
  - build_of_quarkus
  - ceph_storage 6
  - ceph_storage 7
  - ceph_storage 8
  - ceph_storage 9
  - certificate_system 10
  - certificate_system 11
  - data_grid 8
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - enterprise_linux_ai_rhel_ai 3
  - fuse 7
  - jboss_enterprise_application_platform 7
  - jboss_enterprise_application_platform 8
  - jboss_enterprise_application_platform_expansion_pack
  - jboss_web_server 7
  - lightspeed_for_runtimes_operator
  - offline_knowledge_portal
  - openshift_ai_rhoai
  - openshift_dev_spaces
  - satellite 6
  - single_sign_on 7
---

## Overview

DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied automatically whenever @JsonTypeInfo is used without an explicitly configured custom validator. It denies polymorphic resolution only for a fixed set of "unsafe base types", and its isSafeSubType method returns true unconditionally for every base type outside that set. java.lang.Comparable was absent from the list despite being implemented by a very large fraction of JDK and application classes, comparable in breadth to java.io.Serializable, which is on the list for that reason. An application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, and no custom PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. This yields an attacker-controlled object instantiation primitive; a demonstrated case constructs a java.io.File for an arbitrary attacker-chosen path, which becomes path-traversal-adjacent if the application subsequently calls path-sensitive methods on the value. No class implementing Comparable has been identified that yields code execution through deserialization alone. Global Default Typing via activateDefaultTyping is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument. This affects com.fasterxml.jackson.core:jackson-databind from 2.11.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from 3.0.0 before 3.1.6 and from 3.2.0 before 3.2.2. Users should upgrade to 2.18.10, 2.21.6, 2.22.2, 3.1.6, or 3.2.2.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Exploit Intelligence, OpenShift Developer Tools and Services, OpenShift Serverless, Red Hat AI Inference Server, Red Hat AMQ Broker 7, Red Hat Ansible Automation Platform 2, … · no fix planned: Exploit Intelligence, OpenShift Developer Tools and Services, Red Hat Ansible Automation Platform 2, Red Hat build of Apicurio Registry 3, … · updated 2026-09-09 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-83557.json)