Apache Tomcat has an Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Affected scope and exposure questions

The current feed maps org.apache.tomcat.embed:tomcat-embed-core (maven), org.apache.tomcat.embed:tomcat-embed-core (maven), org.apache.tomcat.embed:tomcat-embed-core (maven), org.apache.tomcat:tomcat (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.

Recommended response

1. 1Check inventory. Check lockfiles and deployed manifests for org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat.embed:tomcat-embed-core.
2. 2Review the reported fix. Update org.apache.tomcat.embed:tomcat-embed-core to 9.0.116; org.apache.tomcat.embed:tomcat-embed-core to 10.1.54; org.apache.tomcat.embed:tomcat-embed-core to 11.0.21; org.apache.tomcat:tomcat to 9.0.116; org.apache.tomcat:tomcat to 10.1.54; org.apache.tomcat:tomcat to 11.0.21; org.apache.tomcat:tomcat-catalina to 9.0.116; org.apache.tomcat:tomcat-catalina to 10.1.54; org.apache.tomcat:tomcat-catalina to 11.0.21 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

1. Published upstream

   Apr 9, 2026

   Evidence: source:osv:source_dates:source-dates:record

2. Source modified

   Sep 10, 2026

   Evidence: source:osv:source_dates:source-dates:record

3. First seen by HOL

   Aug 7, 2026

Sources and claim methodology

• GitHub security advisorygithub.com
• Source referencelists.apache.org
• NVD vulnerability recordnvd.nist.gov
• Source referenceopenwall.com