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Low

Improper validation of certificate with host mismatch in Apache Log4j SMTP appender

  • Disclosed: 05.06.2020
  • Updated: 11.10.2026 12:22

Improper validation of certificate with host mismatch in Apache Log4j SMTP appender prior to version 2.13.2. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through that appender.

Affected software

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PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.logging.log4j:log4j >= 2.13.0, < 2.13.2, >= 2.4.0, < 2.12.3, < 2.3.2 2.13.2, 2.12.3, 2.3.2
Java / Kotlin (Maven) org.apache.logging.log4j:log4j-core >= 2.13.0, < 2.13.2, >= 2.4.0, < 2.12.3, < 2.3.2 2.13.2, 2.12.3, 2.3.2

References

CVSS score 3.7/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE)
CWE-295
Platform
Java / Kotlin (Maven)
Package
org.apache.logging.log4j:log4j, org.apache.logging.log4j:log4j-core
Disclosed
05.06.2020
Updated
11.10.2026 12:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-vwqq-5vrc-xw9h - CC BY 4.0

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

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.

All (11) in the archive
Total entries
11
First → latest
01.2020 04.2026
Without a fix
0
Exploited in attacks
2

Severity breakdown

  • Critical 3
  • High 2
  • Medium 5
  • Low 1

Disclosures per year

Severity:
  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. Apache Log4j2 vulnerable to Improper Input Validation and Uncontrolled Recursion
    High · 8.6 CVE-2021-45105 >= 2.4.0, < 2.12.3, >= 2.13.0, < 2.17.0, < 2.3.1 2.12.3, 2.17.0, 2.3.1
  3. Incomplete fix for Apache Log4j vulnerability
    Critical · 9.0 Exploited in attacks CVE-2021-45046 >= 2.13.0, < 2.16.0, >= 2.4.0, < 2.12.2, < 2.3.1 2.16.0, 2.12.2, 2.3.1
  4. Remote code injection in Log4j
    Critical · 10.0 Exploited in attacks CVE-2021-44228 >= 2.13.0, < 2.15.0, >= 2.0-beta9, < 2.3.1, >= 2.4, < 2.12.2 2.15.0, 2.3.1, 2.12.2
  5. Improper validation of certificate with host mismatch in Apache Log4j SMTP appender this entry
    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
  6. Deserialization of Untrusted Data in Log4j
    Critical · 9.8 CVE-2017-5645 >= 2.0, < 2.8.2 2.8.2

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