Описание
jackson-databind has an array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray)
Summary
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.
Impact
Applications using BasicPolymorphicTypeValidator with allowIfSubTypeIsArray() as a safeguard get no protection for concrete array component types; an attacker controlling JSON can instantiate non-allowlisted types via an array wrapper, re-opening the gadget-instantiation risk PTV is meant to prevent.
Affected / Patched (verified via git tag --contains)
- 2.18 line:
>= 2.10.0, < 2.18.8-> fixed in 2.18.8 - 2.19-2.21 line:
>= 2.19.0, < 2.21.4-> fixed in 2.21.4 - 3.x line:
>= 3.0.0, < 3.1.4-> fixed in 3.1.4
PolymorphicTypeValidator was added in 2.10.0 so vulnerability N/A for versions prior to that.
Severity / CWE
Maintainer: significant. Reporter: HIGH. CWE-184 (Incomplete List of Disallowed Inputs); related CWE-502.
Upstream fix
FasterXML/jackson-databind#5981; fix PR #5983 (24529da), 2.18 backport PR #5984 (01d1692). Released 2026-06-04 in 2.18.8 / 2.21.4 / 3.1.4.
Credits
Omkhar Arasaratnam (@omkhar) - finder.
Ссылки
- https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-rmj7-2vxq-3g9f
- https://nvd.nist.gov/vuln/detail/CVE-2026-54513
- https://github.com/FasterXML/jackson-databind/issues/5983
- https://github.com/FasterXML/jackson-databind/issues/5981
- https://github.com/FasterXML/jackson-databind/pull/5984
- https://github.com/FasterXML/jackson-databind/commit/24529da29fdf46ff94ca38de9ebf31cd188f5e8e
- https://github.com/FasterXML/jackson-databind/commit/01d1692c8d0ed03e51a0e3c4f8a9e6908e4931e5
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54513.json
- https://bugzilla.redhat.com/show_bug.cgi?id=2492010
- https://access.redhat.com/security/cve/CVE-2026-54513
- https://access.redhat.com/errata/RHSA-2026:44271
- https://access.redhat.com/errata/RHSA-2026:44066
- https://access.redhat.com/errata/RHSA-2026:44065
- https://access.redhat.com/errata/RHSA-2026:44064
- https://access.redhat.com/errata/RHSA-2026:44063
- https://access.redhat.com/errata/RHSA-2026:44062
- https://access.redhat.com/errata/RHSA-2026:44061
- https://access.redhat.com/errata/RHSA-2026:43400
- https://access.redhat.com/errata/RHSA-2026:43218
- https://access.redhat.com/errata/RHSA-2026:41951
- https://access.redhat.com/errata/RHSA-2026:40895
- https://access.redhat.com/errata/RHSA-2026:36839
Пакеты
com.fasterxml.jackson.core:jackson-databind
>= 2.10.0, < 2.18.8
2.18.8
com.fasterxml.jackson.core:jackson-databind
>= 2.19.0, < 2.21.4
2.21.4
com.fasterxml.jackson.core:jackson-databind
>= 3.0.0, < 3.1.4
3.1.4
tools.jackson.core:jackson-databind
>= 3.0.0, < 3.1.4
3.1.4
Связанные уязвимости
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.
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.
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.
jackson-databind contains the general-purpose data-binding functionali ...
