GHSA-w35j-pv5h-q9q9
Apache Log4j JSON Template Layout: Improper serialization of non-finite floating-point values in JsonTemplateLayout
Quick fix
GHSA-w35j-pv5h-q9q9 — org.apache.logging.log4j:log4j-layout-template-json: upgrade to the fixed version with the command below.
# pom.xml: bump <version>2.25.4</version> for org.apache.logging.log4j:log4j-layout-template-jsonDetails
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 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.
Are you affected?
Enter the version of the package you're using.
Affected packages
2.14.0Fixed in: 2.25.4# pom.xml: bump <version>2.25.4</version> for org.apache.logging.log4j:log4j-layout-template-json3.0.0-alpha1No fixed version published yet for org.apache.logging.log4j:log4j-layout-template-json (maven). Pin to a known-safe version or switch to an alternative.
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-34481[ADVISORY]
- https://github.com/apache/logging-log4j2/pull/4080[WEB]
- https://github.com/apache/logging-log4j2[PACKAGE]
- https://lists.apache.org/thread/n34zdv00gbkdbzt2rx9rf5mqz6lhopcv[WEB]
- https://logging.apache.org/cyclonedx/vdr.xml[WEB]
- https://logging.apache.org/log4j/2.x/manual/json-template-layout.html[WEB]
- https://logging.apache.org/security.html#CVE-2026-34481[WEB]
- http://www.openwall.com/lists/oss-security/2026/04/10/10[WEB]