Improper Encoding or Escaping of Output Affecting org.apache.tomcat:tomcat-catalina package, versions [,9.0.117)[10.1.0-M1,10.1.54)[11.0.0-M1,11.0.21)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-ORGAPACHETOMCAT-15989811
- published12 Apr 2026
- disclosed8 Apr 2026
- creditBartlomiej Dmitruk
Introduced: 8 Apr 2026
CVE-2026-34483 (opens in a new tab)How to fix?
Upgrade org.apache.tomcat:tomcat-catalina to version 9.0.117, 10.1.54, 11.0.21 or higher.
Overview
org.apache.tomcat:tomcat-catalina is a Tomcat Servlet Engine Core Classes and Standard implementations.
Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output in JsonAccessLogValve(), which relies on an unescaped append() in generating JSON logs. If non-default values are used for the Connector attributes relaxedPathChars or relaxedQueryChars, an attacker can inject malicious JSON into logs.