Improper Encoding or Escaping of Output Affecting logstash-9.2-with-output-opensearch package, versions *


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.13% (32nd percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-LOGSTASH92WITHOUTPUTOPENSEARCH-16327131
  • published1 May 2026
  • disclosed10 Apr 2026

Introduced: 10 Apr 2026

CVE-2026-34479  (opens in a new tab)
CWE-116  (opens in a new tab)

How to fix?

There is no fixed version for Minimos:latest logstash-9.2-with-output-opensearch.

NVD Description

Note: Versions mentioned in the description apply only to the upstream logstash-9.2-with-output-opensearch package and not the logstash-9.2-with-output-opensearch package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

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 containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.

Two groups of users are affected:

  • Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.
  • Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class.

Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.

Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.

CVSS Base Scores

version 3.1