Home

Description

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.

PUBLISHED Reserved 2026-03-28 | Published 2026-04-10 | Updated 2026-04-10 | Assigner apache




MEDIUM: 6.3CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N

Problem types

CWE-297 Improper Validation of Certificate with Host Mismatch

Product status

Default status
unaffected

2.12.0 (maven) before 2.25.4
affected

3.0.0-alpha1 (maven)
affected

Timeline

2025-12-20:Vulnerability reported by Samuli Leinonen
2025-12-30:Candidate patch shared internally by Piotr P. Karwasz
2026-02-25:Independent report received from Naresh Kandula
2026-03-01:Independent report received from Vitaly Simonovich
2026-03-02:Independent report received from Raijuna
2026-03-08:Independent report received from Danish Siddiqui
2026-03-19:Independent report received from Markus Magnuson
2026-03-21:Independent report received from Haruki Oyama
2026-03-24:Fix shared publicly by Piotr P. Karwasz as pull request #4075
2026-03-28:Log4j 2.25.4 released

Credits

Samuli Leinonen (original reporter) finder

Naresh Kandula (independently) finder

Vitaly Simonovich (independently) finder

Raijuna (independently) finder

Danish Siddiqui (djvirus, independently) finder

Markus Magnuson (independently) finder

Haruki Oyama (Waseda University, independently) finder

References

github.com/apache/logging-log4j2/pull/4075 patch

logging.apache.org/security.html vendor-advisory

logging.apache.org/cyclonedx/vdr.xml vendor-advisory

logging.apache.org/log4j/2.x/manual/appenders/network.html related

lists.apache.org/thread/lkx8cl46t2bvkcwfcb2pd43ygc097lq4 vendor-advisory

cve.org (CVE-2026-34477)

nvd.nist.gov (CVE-2026-34477)

Download JSON