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Critical

Deserialization of Untrusted Data in Log4j

  • Disclosed: 06.01.2020
  • Updated: 11.10.2026 12:22

Included in Log4j 1.2 is a SocketServer class that is vulnerable to deserialization of untrusted data which can be exploited to remotely execute arbitrary code when combined with a deserialization gadget when listening to untrusted network traffic for log data. This affects Log4j versions 1.2 up to 1.2.17.

Users are advised to migrate to org.apache.logging.log4j:log4j-core.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) log4j:log4j >= 1.2, <= 1.2.17 no fix
Java / Kotlin (Maven) org.zenframework.z8.dependencies.commons:log4j-1.2.17 = 2.0 no fix

References

CVSS score 9.8/10
CVSS vector
CVSS:3.1/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
log4j:log4j, org.zenframework.z8.dependencies.commons:log4j-1.2.17
Disclosed
06.01.2020
Updated
11.10.2026 12:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-2qrg-x229-3v8q - CC BY 4.0

Vulnerability history: 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
6
First → latest
01.2020 03.2023
Without a fix
5
Exploited in attacks
0

Severity breakdown

  • Critical 3
  • High 3

Disclosures per year

  1. Apache Log4j 1.x (EOL) allows Denial of Service (DoS)
    High · 7.5 CVE-2023-26464 >= 1.0.4, < 2.0 2.0
  2. Deserialization of Untrusted Data in Log4j 1.x
    High · 8.8 CVE-2022-23302 <= 1.2.17 no fix
  3. SQL Injection in Log4j 1.2.x
    Critical · 9.8 CVE-2022-23305 <= 1.2.17 no fix
  4. Deserialization of Untrusted Data in Apache Log4j
    Critical · 9.8 CVE-2022-23307 <= 1.2.17 no fix
  5. JMSAppender in Log4j 1.2 is vulnerable to deserialization of untrusted data
    High · 7.5 CVE-2021-4104 >= 1.2.0, <= 1.2.17 no fix
  6. Deserialization of Untrusted Data in Log4j this entry
    Critical · 9.8 CVE-2019-17571 >= 1.2, <= 1.2.17 no fix

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