Security Bulletin: Log4j Core TLS hostname verification bypass via verifyHostName XML attribute allows man-in-the-middle attacks on SMTP/Socket/Syslog appenders.

Summary Vulnerabilities have been identified in Apache Log4j Core affecting TLS security and log integrity. The first leaves TLS hostname verification silently ineffective through version 2.25.3, exposing SMTP, Socket, and Syslog appenders to man-in-the-middle attacks. The second introduces CRLF...

Security Bulletin: Log4j Core TLS hostname verification bypass via verifyHostName XML attribute allows man-in-the-middle attacks on SMTP/Socket/Syslog appenders.

Summary Vulnerabilities have been identified in Apache Log4j Core versions up to 2.25.3 and the Log4j 1-to-2 bridge, covering TLS hostname verification bypass, CRLF log injection, and malformed XML output due to improper character escaping. Collectively, these issues expose applications to...

Security Bulletin: IBM App Connect Enterprise and IBM Integration Bus for z/OS are vulnerable to multiple vulnerabilities due to Apache Log4j ( CVE-2026-34477, CVE-2026-34478, CVE-2026-34479 & CVE-2026-34480 )

Summary IBM App Connect Enterprise and IBM Integration Bus for z/OS are vulnerable to multiple vulnerabilities due to Apache Log4j. Vulnerability Details CVEID:CVE-2026-34477 DESCRIPTION: The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addresse...

SUSE CVE-2026-34477

The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.htmllog4j2.sslVerifyHostName system property, but no...

GHSA-445C-VH5M-36RJ Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility

Apache Log4j Core's Rfc5424Layout, in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes. Two distinct issues affect users of stream-based syslog services who configure Rfc5424Layout directly:...

GHSA-6HG6-V5C8-FPHQ Apache Log4j Core: `verifyHostName` attribute silently ignored in TLS configuration

The fix for CVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName system property, but not when configured through the verifyHostName attribute of the element. Although the verifyHostName configuration attribute was introduced in Log4...

EUVD-2026-21407

The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.htmllog4j2.sslVerifyHostName system property, but no...

Improper Validation of Certificate with Host Mismatch

Overview org.apache.logging.log4j:log4j-core is a logging library for Java. Affected versions of this package are vulnerable to Improper Validation of Certificate with Host Mismatch due to the lack of TLS hostname verification in the SocketAppender component when configured through the...

Improper Output Neutralization for Logs

Overview org.apache.logging.log4j:log4j-core is a logging library for Java. Affected versions of this package are vulnerable to Improper Output Neutralization for Logs in the Rfc5424Layout plugin due to newLineEscape and useTlsMessageFormat configuration attributes being silently renamed, leading...

CVE-2026-34477

The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.htmllog4j2.sslVerifyHostName system property, but no...

UBUNTU-CVE-2026-34477

The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.htmllog4j2.sslVerifyHostName system property, but no...

UBUNTU-CVE-2026-34478

Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.htmlRFC5424Layout , in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes. Two distinct issues affect user...

CVE-2026-34478 Apache Log4j Core: Log injection in Rfc5424Layout due to silent configuration incompatibility

Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.htmlRFC5424Layout , in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes. Two distinct issues affect user...

CVE-2026-34477

The fix for CVE-2025-68161 https://logging.apache.org/security.htmlCVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.htmllog4j2.sslVerifyHostName system property, but no...

SUSE CVE-2006-0743

Format string vulnerability in LocalSyslogAppender in Apache log4net 1.2.9 might allow remote attackers to cause a denial of service memory corruption and termination via unknown vectors...