Log4Cxx

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx_1_1xml_1_1XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets in log messages, NDC, and MDC property keys and values, producing invalid XML output. Conforming XML parsers must reject such documents with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. An attacker who can influence logged data can exploit this to suppress individual log records, impairing audit trails and detection of malicious activity. Users are advised to upgrade to Apache Log4cxx 1.7.0, which fixes this issue.

Published: 2026-04-10T15:45:52.895Z
Updated: 2026-04-10T17:29:20.009Z

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx. When using JSONLayout, not all payload bytes are properly escaped. If an attacker-supplied message contains certain non-printable characters, these will be passed along in the message and written out as part of the JSON message. This may prevent applications that consume these logs from correctly interpreting the information within them. This issue affects Apache Log4cxx: before 1.5.0. Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Published: 2025-08-22T18:45:42.611Z
Updated: 2025-11-04T21:12:54.283Z

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx. When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur: * Log4cxx is configured to use HTMLLayout. * Logger name comes from an untrusted string * Logger with compromised name logs a message * User opens the generated HTML log file in their browser, leading to potential XSS Because logger names are generally constant strings, we assess the impact to users as LOW This issue affects Apache Log4cxx: before 1.5.0. Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Published: 2025-08-22T18:46:46.205Z
Updated: 2025-11-04T21:12:52.982Z

SQL injection in Log4cxx when using the ODBC appender to send log messages to a database.  No fields sent to the database were properly escaped for SQL injection.  This has been the case since at least version 0.9.0(released 2003-08-06) Note that Log4cxx is a C++ framework, so only C++ applications are affected. Before version 1.1.0, the ODBC appender was automatically part of Log4cxx if the library was found when compiling the library.  As of version 1.1.0, this must be both explicitly enabled in order to be compiled in. Three preconditions must be met for this vulnerability to be possible: 1. Log4cxx compiled with ODBC support(before version 1.1.0, this was auto-detected at compile time) 2. ODBCAppender enabled for logging messages to, generally done via a config file 3. User input is logged at some point. If your application does not have user input, it is unlikely to be affected. Users are recommended to upgrade to version 1.1.0 which properly binds the parameters to the SQL statement, or migrate to the new DBAppender class which supports an ODBC connection in addition to other databases. Note that this fix does require a configuration file update, as the old configuration files will not configure properly.  An example is shown below, and more information may be found in the Log4cxx documentation on the ODBCAppender. Example of old configuration snippet: <appender name="SqlODBCAppender" class="ODBCAppender">     <param name="sql" value="INSERT INTO logs (message) VALUES ('%m')" />     ... other params here ... </appender> The migrated configuration snippet with new ColumnMapping parameters: <appender name="SqlODBCAppender" class="ODBCAppender">     <param name="sql" value="INSERT INTO logs (message) VALUES (?)" />     <param name="ColumnMapping" value="message"/>     ... other params here ... </appender>

Published: 2023-05-08T08:54:10.234Z
Updated: 2024-10-15T18:24:15.291Z