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Critical

Deserialization of Untrusted Data in Log4j

  • Disclosed: 06.01.2020
  • Updated: 11.10.2026 12:21

In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another application, a specially crafted binary payload can be sent that, when deserialized, can execute arbitrary code.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.logging.log4j:log4j >= 2.0, < 2.8.2 2.8.2
Java / Kotlin (Maven) org.apache.logging.log4j:log4j-core >= 2.0, < 2.8.2 2.8.2

References

CVSS score 9.8/10
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-502
Platform
Java / Kotlin (Maven)
Package
org.apache.logging.log4j:log4j, org.apache.logging.log4j:log4j-core
Disclosed
06.01.2020
Updated
11.10.2026 12:21

Sources and licenses

OSV / GitHub Advisory Database - GHSA-fxph-q3j8-mv87 - CC BY 4.0

Vulnerability history: org.apache.logging.log4j:log4j

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
2
First → latest
01.2020 06.2020
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • Low 1

Disclosures per year

  1. Improper validation of certificate with host mismatch in Apache Log4j SMTP appender
    Low · 3.7 CVE-2020-9488 >= 2.13.0, < 2.13.2, >= 2.4.0, < 2.12.3, < 2.3.2 2.13.2, 2.12.3, 2.3.2
  2. Deserialization of Untrusted Data in Log4j this entry
    Critical · 9.8 CVE-2017-5645 >= 2.0, < 2.8.2 2.8.2

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