How severe is CVE-2026-54513?

CVE-2026-54513 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-54513?

CVE-2026-54513 affects the following packages: com.fasterxml.jackson.core:jackson-databind (Maven), com.fasterxml.jackson.core:jackson-databind (Maven), com.fasterxml.jackson.core:jackson-databind (Maven), tools.jackson.core:jackson-databind (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-54513?

Update com.fasterxml.jackson.core:jackson-databind to 2.18.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54513 is resolved across your whole dependency graph.

How do I detect CVE-2026-54513 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.fasterxml.jackson.core:jackson-databind, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-54513 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2026-54513 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54513 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-54513?

CVE-2026-54513 has an EPSS (Exploit Prediction Scoring System) score of 1.2%, placing it in the 68th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-54513?

CVE-2026-54513 is classified as CWE-184 (CWE-184). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-54513 published, and has it been updated?

CVE-2026-54513 was published on June 23, 2026 and was last updated on September 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2026-54513 — jackson-databind

HIGHFix: FasterXML/jackson-databind@01d1692

CVE-2026-54513 is a high-severity (CVSS 8.1) CWE-184 vulnerability in com.fasterxml.jackson.core:jackson-databind. A fix is available for com.fasterxml.jackson.core:jackson-databind — see the affected versions and patch details below.

jackson-databind: Array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray)

Also known asGHSA-rmj7-2vxq-3g9f

Published

Jun 23, 2026

Updated

Sep 16, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Sep 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54513.

EPSS Exploitation Probability

via FIRST.org ↗

1.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs68th percentile — riskier than 68% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-54513 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 380,066 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

4 pkgs affected

☕com.fasterxml.jackson.core:jackson-databind☕com.fasterxml.jackson.core:jackson-databind☕com.fasterxml.jackson.core:jackson-databind☕tools.jackson.core:jackson-databind

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.fasterxml.jackson.core:jackson-databind`	≥ 2.10.0&&< 2.18.8	2.18.8`com.fasterxml.jackson.core:jackson-databind:2.18.8`
☕Maven	`com.fasterxml.jackson.core:jackson-databind`	≥ 2.19.0&&< 2.21.4	2.21.4`com.fasterxml.jackson.core:jackson-databind:2.21.4`
☕Maven	`com.fasterxml.jackson.core:jackson-databind`	≥ 3.0.0&&< 3.1.4	3.1.4`com.fasterxml.jackson.core:jackson-databind:3.1.4`
☕Maven	`tools.jackson.core:jackson-databind`	≥ 3.0.0&&< 3.1.4	3.1.4`tools.jackson.core:jackson-databind:3.1.4`

Affected Products

1 product · 3 configurations

Application

jackson-databindfasterxml

≥ 3.0.0 && < 3.1.4

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.fasterxml.jackson.core:jackson-databind, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.fasterxml.jackson.core:jackson-databind to 2.18.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54513 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This Important flaw in `jackson-databind` allows for a security bypass, enabling arbitrary code execution. The vulnerability arises from insufficient validation of array component types by `BasicPolymorphicTypeValidator`, which permits deserialization of unallowlisted types when processing untrusted input. This bypass…

Workaround published by Red Hat

Upgrade to version 2.18.8, 2.21.4, or 3.1.4 or later to address this vulnerability. If upgrading is not immediately possible, remove BasicPolymorphicTypeValidator.Builder.allowIfSubTypeIsArray() from the application’s ObjectMapper configuration to eliminate the affected deserialization path. Rebuild and restart the application to apply the configuration change. As an additional mitigation, disable polymorphic deserialization of untrusted data where possible by avoiding or removing default typing features such as activateDefaultTyping() or enableDefaultTyping(). When polymorphic deserialization is required, restrict allowed subtypes using a strict whitelist of trusted application packages…

Source: Red Hat security advisory for CVE-2026-54513 (CC BY 4.0)

Product	Fixed in	Advisory
AMQ Clients 2026.Q3	`jackson-databind`	RHSA-2026:69459
Cryostat 4 on RHEL 9	`cryostat/cryostat-reports-rhel9:4.2.0-13`	RHSA-2026:48151
Red Hat AMQ Broker 7.13.6	`jackson-databind`	RHSA-2026:66545
Red Hat AMQ Broker 7.14.1	`jackson-databind`	RHSA-2026:66488
Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16	`jackson-databind`	RHSA-2026:54622
Red Hat build of Keycloak 26.4	`rhbk/keycloak-operator-bundle:26.4.14-1`	RHSA-2026:50847
Red Hat build of Keycloak 26.4.14	`jackson-databind`	RHSA-2026:50846
Red Hat build of Keycloak 26.6	`rhbk/keycloak-operator-bundle:26.6.5-1`	RHSA-2026:50849

Frequently Asked Questions

## 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 `Basic

O3 Security · Impact-Aware SCA

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