Advisories for Maven/Org.apache.logging.log4j/Log4j-Core package

2023

Uncontrolled Resource Consumption

** UNSUPPORTED WHEN ASSIGNED ** When using the Chainsaw or SocketAppender components with Log4j 1.x on JRE less than 1.7, an attacker that manages to cause a logging entry involving a specially-crafted (ie, deeply nested) hashmap or hashtable (depending on which logging component is in use) to be processed could exhaust the available memory in the virtual machine and achieve Denial of Service when the object is deserialized. This issue …

2021

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

It was found that the fix to address CVE-2021-44228 in Apache Log4j was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in …

Deserialization of Untrusted Data

JMSAppender in Log4j is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration. The attacker can provide TopicBindingName and TopicConnectionFactoryBindingName configurations causing JMSAppender to perform JNDI requests that result in remote code execution in a similar fashion to CVE-2021-44228. Note this issue only affects Log4j when specifically configured to use JMSAppender, which is not the default. Apache Log4j reached end of life in …

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j, this behavior has been disabled by default. In previous releases (>2.10) this behavior can be mitigated by setting system property log4j2.formatMsgNoLookups to …

2020