Summary

Log4j versions prior to 2.16.0 are subject to a remote code execution vulnerability via the ldap JNDI parser. As per Apache's Log4j security guide: Apache Log4j2 <=2.14.1 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 2.16.0, this behavior has been disabled by default.

Log4j version 2.15.0 contained an earlier fix for the vulnerability, but that patch did not disable attacker-controlled JNDI lookups in all situations. For more information, see the Updated advice for version 2.16.0 section of this advisory.

Impact

Logging untrusted or user controlled data with a vulnerable version of Log4J may result in Remote Code Execution (RCE) against your application. This includes untrusted data included in logged errors such as exception traces, authentication failures, and other unexpected vectors of user controlled input.

Affected versions

Any Log4J version prior to v2.15.0 is affected to this specific issue.

The v1 branch of Log4J which is considered End Of Life (EOL) is vulnerable to other RCE vectors so the recommendation is to still update to 2.16.0 where possible.

Security releases Additional backports of this fix have been made available in versions 2.3.1, 2.12.2, and 2.12.3

Affected packages Only the org.apache.logging.log4j:log4j-core package is directly affected by this vulnerability. The org.apache.logging.log4j:log4j-api should be kept at the same version as the org.apache.logging.log4j:log4j-core package to ensure compatability if in use.

Remediation Advice

Updated advice for version 2.16.0

The Apache Logging Services team provided updated mitigation advice upon the release of version 2.16.0, which disables JNDI by default and completely removes support for message lookups. Even in version 2.15.0, lookups used in layouts to provide specific pieces of context information will still recursively resolve, possibly triggering JNDI lookups. This problem is being tracked as CVE-2021-45046. More information is available on the GitHub Security Advisory for CVE-2021-45046.

Users who want to avoid attacker-controlled JNDI lookups but cannot upgrade to 2.16.0 must ensure that no such lookups resolve to attacker-provided data and ensure that the the JndiLookup class is not loaded.

Please note that Log4J v1 is End Of Life (EOL) and will not receive patches for this issue. Log4J v1 is also vulnerable to other RCE vectors and we recommend you migrate to Log4J 2.16.0 where possible.

Impact

The fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allow 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 a remote code execution (RCE) attack.

Affected packages Only the org.apache.logging.log4j:log4j-core package is directly affected by this vulnerability. The org.apache.logging.log4j:log4j-api should be kept at the same version as the org.apache.logging.log4j:log4j-core package to ensure compatability if in use.

Mitigation

Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default. This issue can be mitigated in prior releases (< 2.16.0) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-.jar org/apache/logging/log4j/core/lookup/JndiLookup.class).

Log4j 2.15.0 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property log4j2.formatMsgNoLookups to true do NOT mitigate this specific vulnerability.

A vulnerability has been identified in Opcenter Execution Foundation (All versions < V2501.0001), Opcenter Intelligence (All versions < V2501.0001), Opcenter Quality (All versions < V2512), Opcenter RDnL (All versions < V2410), SIMATIC PCS neo V4.0 (All versions), SIMATIC PCS neo V4.1 (All versions < V4.1 Update 3), SIMATIC PCS neo V5.0 (All versions < V5.0 Update 1), SINEC NMS (All versions if operated in conjunction with UMC < V2.15), Totally Integrated Automation Portal (TIA Portal) V16 (All versions), Totally Integrated Automation Portal (TIA Portal) V17 (All versions), Totally Integrated Automation Portal (TIA Portal) V18 (All versions), Totally Integrated Automation Portal (TIA Portal) V19 (All versions). Affected products contain a heap-based buffer overflow vulnerability in the integrated UMC component. This could allow an unauthenticated remote attacker to execute arbitrary code.

Rejected reason: This CVE ID is a duplicate of CVE-2025-26494.

Rejected reason: This CVE ID is a duplicate of CVE-2025-26495.

A vulnerability has been identified in Opcenter Execution Discrete (All versions < V3.2), Opcenter Execution Foundation (All versions < V3.2), Opcenter Execution Process (All versions < V3.2), Opcenter Intelligence (All versions < V3.3), Opcenter Quality (All versions < V11.3), Opcenter RD&L (V8.0), SIMATIC IT LMS (All versions < V2.6), SIMATIC IT Production Suite (All versions < V8.0), SIMATIC Notifier Server for Windows (All versions), SIMATIC PCS neo (All versions < V3.0 SP1), SIMATIC STEP 7 (TIA Portal) V15 (All versions < V15.1 Update 5), SIMATIC STEP 7 (TIA Portal) V16 (All versions < V16 Update 2), SIMOCODE ES V15.1 (All versions < V15.1 Update 4), SIMOCODE ES V16 (All versions < V16 Update 1), Soft Starter ES V15.1 (All versions < V15.1 Update 3), Soft Starter ES V16 (All versions < V16 Update 1). Sending a specially crafted packet to the affected service could cause a partial remote denial-of-service, that would cause the service to restart itself.

A vulnerability has been identified in Opcenter Execution Discrete (All versions < V3.2), Opcenter Execution Foundation (All versions < V3.2), Opcenter Execution Process (All versions < V3.2), Opcenter Intelligence (All versions < V3.3), Opcenter Quality (All versions < V11.3), Opcenter RD&L (V8.0), SIMATIC IT LMS (All versions < V2.6), SIMATIC IT Production Suite (All versions < V8.0), SIMATIC Notifier Server for Windows (All versions), SIMATIC PCS neo (All versions < V3.0 SP1), SIMATIC STEP 7 (TIA Portal) V15 (All versions < V15.1 Update 5), SIMATIC STEP 7 (TIA Portal) V16 (All versions < V16 Update 2), SIMOCODE ES V15.1 (All versions < V15.1 Update 4), SIMOCODE ES V16 (All versions < V16 Update 1), Soft Starter ES V15.1 (All versions < V15.1 Update 3), Soft Starter ES V16 (All versions < V16 Update 1). Sending multiple specially crafted packets to the affected service could cause a partial remote denial-of-service, that would cause the service to restart itself. On some cases the vulnerability could leak random information from the remote service.

A vulnerability has been identified in Opcenter Execution Discrete (All versions < V3.2), Opcenter Execution Foundation (All versions < V3.2), Opcenter Execution Process (All versions < V3.2), Opcenter Intelligence (All versions < V3.3), Opcenter Quality (All versions < V11.3), Opcenter RD&L (V8.0), SIMATIC Notifier Server for Windows (All versions), SIMATIC PCS neo (All versions < V3.0 SP1), SIMATIC STEP 7 (TIA Portal) V15 (All versions < V15.1 Update 5), SIMATIC STEP 7 (TIA Portal) V16 (All versions < V16 Update 2), SIMOCODE ES V15.1 (All versions < V15.1 Update 4), SIMOCODE ES V16 (All versions < V16 Update 1), Soft Starter ES V15.1 (All versions < V15.1 Update 3), Soft Starter ES V16 (All versions < V16 Update 1). A component within the affected application calls a helper binary with SYSTEM privileges during startup while the call path is not quoted. This could allow a local attacker with administrative privileges to execute code with SYSTEM level privileges.