CVE-2026-34483: Apache Tomcat

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.

Affected products

• Apache Tomcat: from 9.0.40, before 9.0.117 (fixed in 9.0.117); from 10.1.0, before 10.1.54 (fixed in 10.1.54); from 11.0.0, before 11.0.21 (fixed in 11.0.21)

Published 2026-04-09. Last modified 2026-06-17.