What is CVE-2026-34481?

CVE-2026-34481 is a medium-severity security vulnerability in org.apache.logging.log4j:log4j-layout-template-json (maven), affecting versions >= 2.14.0, < 2.25.4. It is fixed in 2.25.4.

Which versions of org.apache.logging.log4j:log4j-layout-template-json are affected by CVE-2026-34481?

org.apache.logging.log4j:log4j-layout-template-json (maven) versions >= 2.14.0, < 2.25.4 is affected.

Is there a fix for CVE-2026-34481?

Yes. CVE-2026-34481 is fixed in 2.25.4. Upgrade to this version or later.

Is CVE-2026-34481 exploitable, and should I be worried?

Whether CVE-2026-34481 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-34481 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-34481

Q: Is there a fix for CVE-2026-34481?

Yes. CVE-2026-34481 is fixed in 2.25.4. Upgrade to this version or later.

Q: Is CVE-2026-34481 exploitable, and should I be worried?

Whether CVE-2026-34481 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-34481 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-34481?

Upgrade org.apache.logging.log4j:log4j-layout-template-json to 2.25.4 or later.

Summary

Apache Log4j JSON Template Layout: Improper serialization of non-finite floating-point values in JsonTemplateLayout

Apache Log4j's JsonTemplateLayout, in versions up to and including 2.25.3, produces invalid JSON output when log events contain non-finite floating-point values (NaN, Infinity, or -Infinity), which are prohibited by RFC 8259. This may cause downstream log processing systems to reject or fail to index affected records.

An attacker can exploit this issue only if both of the following conditions are met:

The application uses JsonTemplateLayout.
The application logs a MapMessage containing an attacker-controlled floating-point value.

Users are advised to upgrade to Apache Log4j JSON Template Layout 2.25.4, which corrects this issue.

Impact

Affected versions

org.apache.logging.log4j:log4j-layout-template-json (>= 2.14.0, < 2.25.4) org.apache.logging.log4j:log4j-layout-template-json (>= 3.0.0-alpha1, <= 3.0.0-beta3)

Security releases

org.apache.logging.log4j:log4j-layout-template-json → 2.25.4 (maven)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade org.apache.logging.log4j:log4j-layout-template-json to 2.25.4 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-34481? CVE-2026-34481 is a medium-severity security vulnerability in org.apache.logging.log4j:log4j-layout-template-json (maven), affecting versions >= 2.14.0, < 2.25.4. It is fixed in 2.25.4.
Which versions of org.apache.logging.log4j:log4j-layout-template-json are affected by CVE-2026-34481? org.apache.logging.log4j:log4j-layout-template-json (maven) versions >= 2.14.0, < 2.25.4 is affected.
Is there a fix for CVE-2026-34481? Yes. CVE-2026-34481 is fixed in 2.25.4. Upgrade to this version or later.
Is CVE-2026-34481 exploitable, and should I be worried? Whether CVE-2026-34481 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-34481 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-34481? Upgrade org.apache.logging.log4j:log4j-layout-template-json to 2.25.4 or later.