Bug 2457321 (CVE-2026-34481)

Summary:	CVE-2026-34481 org.apache.logging.log4j: Apache Log4j JsonTemplateLayout: Denial of Service via invalid JSON output
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	asoldano, ataylor, bbaranow, bmaxwell, bstansbe, chfoley, dbruscin, dlofthou, fmariani, gmalinko, istudens, ivassile, iweiss, janstey, jwon, kvanderr, mcarlett, mosmerov, msvehla, nwallace, pberan, pesilva, pjindal, pmackay, rgodfrey, rhel-process-autobot, rstancel, rstepani, smaestri, swoodman, tcunning, thjenkin, vdosoudi, watson-tool-maintainers, yfang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Apache Log4j's JsonTemplateLayout. This vulnerability allows a remote attacker to disrupt log processing systems. By sending log events that include specific non-numeric floating-point values, the attacker can cause the JsonTemplateLayout to generate invalid JSON output. This invalid output can then lead to downstream systems rejecting or failing to index these logs, effectively causing a denial of service for log analysis.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2457909
Bug Blocks:

Description OSIDB Bzimport 2026-04-10 16:02:08 UTC

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.