Apache
Apache Log4j: vulnerabilities and CVEs
Apache Log4j has 21 published vulnerabilities, 8 of them in the last 12 months. 6 are rated critical and 2 are listed by CISA as actively exploited.
CVEs21
Last 12 months8
Critical6
Actively exploited2
All vulnerabilities in the catalogue →⭐ Follow this technology
🔴 Actively exploited (CISA KEV)
| CVE | Severity | EPSS | Active exploitation | Published | Description |
|---|---|---|---|---|---|
| CVE-2021-45046 | Critical (9) | 100% | ⚠ Active exploitation | Dec 14, 2021 | It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the… |
| CVE-2021-44228 | Critical (10) | 100% | ⚠ Active exploitation | Dec 10, 2021 | Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other… |
Latest vulnerabilities
| CVE | Severity | EPSS | Active exploitation | Published | Description |
|---|---|---|---|---|---|
| CVE-2026-85656 | High (8.5) | 1.1% | — | Sep 4, 2026 | An OS command injection issue in the log4j-cve-2021-44228-hotpatch package in Amazon Linux before 1.3-9 might allow a local user to execute arbitrary commands with root privileges via a Java process whose executable… |
| CVE-2026-49844 | Medium (6.3) | 0.81% | — | Jul 10, 2026 | Improper encoding of non-finite floating-point values during MapMessage JSON serialization in Apache Log4j API produces output that is not valid JSON. This issue affects Apache Log4j API versions 2.13.1 through 2.25.4… |
| CVE-2026-34481 | Medium (6.3) | 0.85% | — | Apr 10, 2026 | Apache Log4j's JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in versions up to and including 2.25.3, produces invalid JSON output when log events contain non-finite… |
| CVE-2026-34480 | Medium (6.9) | 1.2% | — | Apr 10, 2026 | 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… |
| CVE-2026-34479 | Medium (6.9) | 0.91% | — | Apr 10, 2026 | 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… |
| CVE-2026-34478 | Medium (6.9) | 1.2% | — | Apr 10, 2026 | 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… |
| CVE-2026-34477 | Medium (6.3) | 0.50% | — | Apr 10, 2026 | 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… |
| CVE-2025-68161 | Medium (6.3) | 0.77% | — | Dec 18, 2025 | 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… |
| CVE-2023-26464 | High (7.5) | 1.9% | — | Mar 10, 2023 | ** 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… |
| CVE-2022-23307 | High (8.8) | 54% | — | Jan 18, 2022 | CVE-2020-9493 identified a deserialization issue that was present in Apache Chainsaw. Prior to Chainsaw V2.0 Chainsaw was a component of Apache Log4j 1.2.x where the same issue exists. |
| CVE-2022-23305 | Critical (9.8) | 67% | — | Jan 18, 2022 | By design, the JDBCAppender in Log4j 1.2.x accepts an SQL statement as a configuration parameter where the values to be inserted are converters from PatternLayout. The message converter, %m, is likely to always be… |
| CVE-2022-23302 | High (8.8) | 64% | — | Jan 18, 2022 | JMSSink in all versions of Log4j 1.x is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration or if the configuration references an LDAP service the attacker has… |
| CVE-2021-44832 | Medium (6.6) | 98% | — | Dec 28, 2021 | 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 remote code execution (RCE) attack when a configuration uses a JDBC Appender with a JNDI LDAP data… |
| CVE-2021-45105 | Medium (5.9) | 100% | — | Dec 18, 2021 | Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data… |
| CVE-2021-45046 | Critical (9) | 100% | ⚠ Active exploitation | Dec 14, 2021 | It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the… |
| CVE-2021-4104 | High (7.5) | 81% | — | Dec 14, 2021 | 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… |
| CVE-2021-44228 | Critical (10) | 100% | ⚠ Active exploitation | Dec 10, 2021 | Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other… |
| CVE-2020-9493 | Critical (9.8) | 4.6% | — | Jun 16, 2021 | A deserialization flaw was found in Apache Chainsaw versions prior to 2.1.0 which could lead to malicious code execution. |
| CVE-2020-9488 | Low (3.7) | 8.1% | — | Apr 27, 2020 | Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through… |
| CVE-2019-17571 | Critical (9.8) | 69% | — | Dec 20, 2019 | Included in Log4j 1.2 is a SocketServer class that is vulnerable to deserialization of untrusted data which can be exploited to remotely execute arbitrary code when combined with a deserialization gadget when listening… |
| CVE-2017-5645 | Critical (9.8) | 90% | — | Apr 17, 2017 | In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another application, a specially crafted binary payload can be sent that, when deserialized,… |