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Vulnerabilities

Vulnerability · CVE-2026-54513

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

Published Jun 16, 2026 · catalog updated Jun 18, 2026 · Array subtype allowlist bypass

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-54513. EPSS is 1.23%. Act only if a listed version of Array subtype allowlist bypass is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Array subtype allowlist bypass).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.23%
Remediation
Version ranges on file
Affected products
maven com.fasterxml.jackson.core:jackson-databind · maven tools.jackson.core:jackson-databind

## Summary allowlists any array type based only on , without validating the array's component (element) type against the configured allowlist. A PTV built with plus an explicit concrete-type allowlist therefore still permits even though 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 with 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 ) - 2.18 line: -> fixed in **2.18.8** - 2.19-2.21 line: -> fixed in **2.21.4** - 3.x line: -> fixed in **3.1.4** 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 ( ), 2.18 backport PR #5984 ( ). Released 2026-06-04 in 2.18.8 / 2.21.4 / 3.1.4. ## Credits Omkhar Arasaratnam (@omkhar) - finder.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • maven com.fasterxml.jackson.core:jackson-databind>= 2.10.0, < 2.18.8
  • maven com.fasterxml.jackson.core:jackson-databind>= 2.19.0, < 2.21.4
  • maven tools.jackson.core:jackson-databind>= 3.0.0, < 3.1.4

How to fix CVE-2026-54513

  • Upgrade

    CVE-2026-54513 lists a fix boundary at 2.18.8. Compare the installed build with that boundary before you change production.

  • Version check

    Affected < 2.18.8

  • Advisory

    Open the inventory_github record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-54513. EPSS is 1.23%. Act only if a listed version of Array subtype allowlist bypass is installed.

Which versions are affected?

Compare what you have installed with >= 2.10.0, < 2.18.8, >= 2.19.0, < 2.21.4, >= 3.0.0, < 3.1.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-184. EPSS 1.23%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Jackson security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 16, 2026 · Maintainer security tabs

    Detected

    ## Summary allowlists any array type based only on , without validating the array's component (element) type against the configured allowlist. A PTV built with plus an explicit concrete-type allowlist therefore still permits even though 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

  2. Jun 18, 2026 · Maintainer security tabs

    Updated

    ## Summary allowlists any array type based only on , without validating the array's component (element) type against the configured allowlist. A PTV built with plus an explicit concrete-type allowlist therefore still permits even though 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

Sources

  • Maintainer security tabsVendor advisoryGHSA-rmj7-2vxq-3g9f

    ## Summary allowlists any array type based only on , without validating the array's component (element) type against the configured allowlist. A PTV built with plus an explicit concrete-type allowlist therefore still permits even though 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

    github.com

Freshness

Last verified in this catalog Nov 2, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Maintainer security tabsNov 2, 2026