Log4J
CVE-2021-4104
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V1 - Encoding and Sanitization Safe deserialization, type allowlists
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, high complexity, low privileges required, no user interaction not required. EPSS exploitation probability: 72.20%. |
| Exploit ScenarioDerived | A remote attacker could execute arbitrary code through malicious serialized objects by sending crafted requests to the affected application. |
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Alert meAnalysisAI
JMSAppender in Log4j 1.2 is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable. Epss exploitation probability 72.2% and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Avoid deserializing untrusted data. Use safe serialization formats (JSON). Implement integrity checks and type allowlists.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in maven
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Deserialization of Untrusted Data (CWE-502), which allows attackers to execute arbitrary code through malicious serialized objects. JMSAppender in Log4j 1.2 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 1.2 when specifically configured to use JMSAppender, which is not the default. Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions. Affected products include: Apache Log4J, Fedoraproject Fedora, Redhat Codeready Studio, Redhat Integration Camel K, Redhat Integration Camel Quarkus.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionCVE.org
JMSAppender in Log4j 1.2 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 1.2 when specifically configured to use JMSAppender, which is not the default. Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions.
Blast Radius
ecosystem impact- 1 maven packages depend on org.zenframework.z8.dependencies.commons:log4j-1.2.17 (1 direct, 0 indirect)
Ecosystem-wide dependent count for version 2.0.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)CVE.org
Apache Log4j2 contains a critical JNDI injection vulnerability known as 'Log4Shell' that allows unauthenticated remote c
In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events
Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursio
Apache Log4j2 versions 2.0-beta7 through 2.17.0 (excluding security fix releases 2.3.2 and 2.12.4) are vulnerable to a r
Included in Log4j 1.2 is a SocketServer class that is vulnerable to deserialization of untrusted data which can be explo
By design, the JDBCAppender in Log4j 1.2.x accepts an SQL statement as a configuration parameter where the values to be
CVE-2020-9493 identified a deserialization issue that was present in Apache Chainsaw. Rated high severity (CVSS 8.8), th
JMSSink in all versions of Log4j 1.x is vulnerable to deserialization of untrusted data when the attacker has write acce
** UNSUPPORTED WHEN ASSIGNED ** When using the Chainsaw or SocketAppender components with Log4j 1.x on JRE less than 1.7
Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. Rated low severity (CVSS 3.7), this
Exploit-DB