Improper Certificate Validation Affecting log4j:2/log4j-jcl package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.11% (30th percentile)

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  • Snyk IDSNYK-RHEL8-LOG4J-16074613
  • published15 Apr 2026
  • disclosed10 Apr 2026

Introduced: 10 Apr 2026

NewCVE-2026-34477  (opens in a new tab)
CWE-295  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:8 log4j:2/log4j-jcl.

NVD Description

Note: Versions mentioned in the description apply only to the upstream log4j:2/log4j-jcl package and not the log4j:2/log4j-jcl package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

The fix for CVE-2025-68161 https://logging.apache.org/security.html#CVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property, but not when configured through the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName attribute of the <Ssl> element.

Although the verifyHostName configuration attribute was introduced in Log4j Core 2.12.0, it was silently ignored in all versions through 2.25.3, leaving TLS connections vulnerable to interception regardless of the configured value.

A network-based attacker may be able to perform a man-in-the-middle attack when all of the following conditions are met:

  • An SMTP, Socket, or Syslog appender is in use.
  • TLS is configured via a nested <Ssl> element.
  • The attacker can present a certificate issued by a CA trusted by the appender's configured trust store, or by the default Java trust store if none is configured. This issue does not affect users of the HTTP appender, which uses a separate verifyHostname https://logging.apache.org/log4j/2.x/manual/appenders/network.html#HttpAppender-attr-verifyHostName attribute that was not subject to this bug and verifies host names by default.

Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.

CVSS Base Scores

version 3.1