CVE-2020-8840Network attack vector

Remote code execution via unblocked JndiConverter gadget

Published Feb 10, 2020 · Updated Aug 4, 2024

Deserialization in FasterXML jackson-databind 2.0.0 through 2.9.10.2 allows remote attackers to execute code via crafted JSON. BeanDeserializerFactory omits org.apache.xbean.propertyeditor.JndiConverter from its denied-class set, allowing polymorphic deserialization to instantiate the gadget and initiate a JNDI lookup. Exploitation requires Default Typing, xbean-reflect on the classpath, and an application that passes attacker-controlled JSON to jackson-databind.

CVSS severity9.8
Critical
EPSS probability26.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in FasterXML jackson-databind 2.0.0 through 2.9.10.2 allows remote attackers to execute code via crafted JSON. BeanDeserializerFactory omits org.apache.xbean.propertyeditor.JndiConverter from its denied-class set, allowing polymorphic deserialization to instantiate the gadget and initiate a JNDI lookup. Exploitation requires Default Typing, xbean-reflect on the classpath, and an application that passes attacker-controlled JSON to jackson-databind.

The record

CVE
CVE-2020-8840
Published
Feb 10, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 10, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.3IBMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
T1190Exploit Public-Facing Application

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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