Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Vulnerabilities
| Vulnerability |
Severity |
 CVSS |
Dependency |
Type |
Fixed in (log4j-core version) |
Remediation Possible** |
| CVE-2026-34480 |
 Medium |
5.8 |
log4j-core-2.25.1.jar |
Direct |
2.25.4 |
❌ |
| CVE-2026-34479 |
Medium |
5.8 |
log4j-core-2.25.1.jar |
Direct |
2.25.4 |
❌ |
| CVE-2026-34478 |
Medium |
5.8 |
log4j-core-2.25.1.jar |
Direct |
2.25.4 |
❌ |
| CVE-2026-34477 |
Medium |
4.0 |
log4j-core-2.25.1.jar |
Direct |
2.25.4 |
❌ |
| CVE-2025-68161 |
Medium |
4.0 |
log4j-core-2.25.1.jar |
Direct |
2.25.3 |
❌ |
**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation
Details
CVE-2026-34480
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
- ❌ log4j-core-2.25.1.jar (Vulnerable Library)
Found in base branch: main
Vulnerability Details
Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets producing invalid XML output whenever a log message or MDC value contains such characters.
The impact depends on the StAX implementation in use:
- JRE built-in StAX: Forbidden characters are silently written to the output, producing malformed XML. Conforming parsers must reject such documents with a fatal error, which may cause downstream log-processing systems to drop the affected records.
- Alternative StAX implementations (e.g., Woodstox https://github.com/FasterXML/woodstox , a transitive dependency of the Jackson XML Dataformat module): An exception is thrown during the logging call, and the log event is never delivered to its intended appender, only to Log4j's internal status logger.
Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue by sanitizing forbidden characters before XML output.
Publish Date: 2026-04-10
URL: CVE-2026-34480
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Release Date: 2026-04-10
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
CVE-2026-34479
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
- ❌ log4j-core-2.25.1.jar (Vulnerable Library)
Found in base branch: main
Vulnerability Details
The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.
Two groups of users are affected:
- Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.
- Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class.
Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.
Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.
Publish Date: 2026-04-10
URL: CVE-2026-34479
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Release Date: 2026-04-10
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
CVE-2026-34478
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
- ❌ log4j-core-2.25.1.jar (Vulnerable Library)
Found in base branch: main
Vulnerability Details
Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.html#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:
- The newLineEscape attribute was silently renamed, causing newline escaping to stop working for users of TCP framing (RFC 6587), exposing them to CRLF injection in log output.
- The useTlsMessageFormat attribute was silently renamed, causing users of TLS framing (RFC 5425) to be silently downgraded to unframed TCP (RFC 6587), without newline escaping.
Users of the SyslogAppender are not affected, as its configuration attributes were not modified.
Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.
Publish Date: 2026-04-10
URL: CVE-2026-34478
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: https://seclists.org/oss-sec/2026/q2/90
Release Date: 2026-04-09
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
CVE-2026-34477
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
- ❌ log4j-core-2.25.1.jar (Vulnerable Library)
Found in base branch: main
Vulnerability Details
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 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 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.
Publish Date: 2026-04-10
URL: CVE-2026-34477
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: None
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: https://seclists.org/oss-sec/2026/q2/89
Release Date: 2026-04-09
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
CVE-2025-68161
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API.
It bundles a rich set of components to assist various use cases:
Appenders targeting files, network sockets, databases, SMTP servers;
Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs;
Filters that can be configured using log event rates, regular expressions, scripts, time, etc.
It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
- ❌ log4j-core-2.25.1.jar (Vulnerable Library)
Found in base branch: main
Vulnerability Details
The Socket Appender in Apache Log4j Core versions 2.0-beta9 through 2.25.2 does not perform TLS hostname verification of the peer certificate, even when the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName configuration attribute or the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property is set to true.
This issue may allow a man-in-the-middle attacker to intercept or redirect log traffic under the following conditions:
- The attacker is able to intercept or redirect network traffic between the client and the log receiver.
- The attacker can present a server certificate issued by a certification authority trusted by the Socket Appender’s configured trust store (or by the default Java trust store if no custom trust store is configured).
Users are advised to upgrade to Apache Log4j Core version 2.25.3, which addresses this issue.
As an alternative mitigation, the Socket Appender may be configured to use a private or restricted trust root to limit the set of trusted certificates.
Publish Date: 2025-12-18
URL: CVE-2025-68161
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: None
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Release Date: 2025-12-17
Fix Resolution: 2.25.3
Step up your Open Source Security Game with Mend here
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Vulnerabilities
**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation
Details
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
Found in base branch: main
Vulnerability Details
Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets producing invalid XML output whenever a log message or MDC value contains such characters.
The impact depends on the StAX implementation in use:
Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue by sanitizing forbidden characters before XML output.
Publish Date: 2026-04-10
URL: CVE-2026-34480
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Release Date: 2026-04-10
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
Found in base branch: main
Vulnerability Details
The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.
Two groups of users are affected:
Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.
Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.
Publish Date: 2026-04-10
URL: CVE-2026-34479
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Release Date: 2026-04-10
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
Found in base branch: main
Vulnerability Details
Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.html#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:
Users of the SyslogAppender are not affected, as its configuration attributes were not modified.
Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.
Publish Date: 2026-04-10
URL: CVE-2026-34478
CVSS 3 Score Details (5.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: https://seclists.org/oss-sec/2026/q2/90
Release Date: 2026-04-09
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
Found in base branch: main
Vulnerability Details
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 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:
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.
Publish Date: 2026-04-10
URL: CVE-2026-34477
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: None
- Availability Impact: None
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: https://seclists.org/oss-sec/2026/q2/89
Release Date: 2026-04-09
Fix Resolution: 2.25.4
Step up your Open Source Security Game with Mend here
Vulnerable Library - log4j-core-2.25.1.jar
A versatile, industrial-grade, and reference implementation of the Log4j API. It bundles a rich set of components to assist various use cases: Appenders targeting files, network sockets, databases, SMTP servers; Layouts that can render CSV, HTML, JSON, Syslog, etc. formatted outputs; Filters that can be configured using log event rates, regular expressions, scripts, time, etc. It contains several extension points to introduce custom components, if needed.
Library home page: https://logging.apache.org/log4j/2.x/
Path to dependency file: /artemis-java-template/pom.xml
Path to vulnerable library: /artemis-java-template/pom.xml
Dependency Hierarchy:
Found in base branch: main
Vulnerability Details
The Socket Appender in Apache Log4j Core versions 2.0-beta9 through 2.25.2 does not perform TLS hostname verification of the peer certificate, even when the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName configuration attribute or the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property is set to true.
This issue may allow a man-in-the-middle attacker to intercept or redirect log traffic under the following conditions:
Users are advised to upgrade to Apache Log4j Core version 2.25.3, which addresses this issue.
As an alternative mitigation, the Socket Appender may be configured to use a private or restricted trust root to limit the set of trusted certificates.
Publish Date: 2025-12-18
URL: CVE-2025-68161
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: None
- Availability Impact: None
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Release Date: 2025-12-17
Fix Resolution: 2.25.3
Step up your Open Source Security Game with Mend here