CVE-2018-21234Network attack vector

Remote code execution via unrestricted class metadata

Published May 21, 2020 · Updated Aug 5, 2024

Deserialization in Jodd JSON before 5.0.4 allows remote attackers to execute arbitrary code through crafted JSON class metadata. MapToBean reads an attacker-controlled class name from configured metadata and passes it to ClassLoaderUtil.loadClass without restricting allowed types. Exposure requires an application to enable setClassMetadataName and parse JSON from an untrusted source; successful exploitation runs code in that process.

CVSS severity9.8
Critical
EPSS probability8.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Jodd JSON before 5.0.4 allows remote attackers to execute arbitrary code through crafted JSON class metadata. MapToBean reads an attacker-controlled class name from configured metadata and passes it to ClassLoaderUtil.loadClass without restricting allowed types. Exposure requires an application to enable setClassMetadataName and parse JSON from an untrusted source; successful exploitation runs code in that process.

The record

CVE
CVE-2018-21234
Published
May 21, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, CAPEC-586
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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